What purpose would this be used for?

Don't think of it as a tiny cable, think of it as a gender bender. You can put on the end of some female cable.
You're more likely to see dongles like this at fixed installations. Like somebody puts a USB port into a wall, like a speaker's podium, or a presentation stand. So one side is fixed, depending on what you want to hook up to it, you might need to have a gender bender.
- Is the cable considered transgender after that ?
  
  USB is bi-directional. So it really doesn't care about the plug gender. Some other protocols are directional, then the plug gender is very important, so adapters for directional protocols tend to be more expensive, it may even require external power.
  Once USB on the go was invented it cease to matter at all.
- What your describing sounds more like a double ended dildo
  
  As long as the double ended dildo provided low impedance electrical through ways, and distinct electrical paths for at least four conduits, with minimal capacitive cross talk... then yes
  
  double ended dildo
  Isn't that just a gender bender for women? Now we just need a double ended fleshlight for equality... And no I'm not going to google that!

Ass to ass
- The stars of username, comment and upvotes
  
  I want to upvote but I cant.

Have you never just wanted to plug 2 PCs into each other back to back?
- Ass to ass as it were
  
  ))><((
  
  Back and forth, forever.

If you think about it, this is the USB equivalent of a double ended dildo
- does this mean there's also double ended flesh lights?
  
  Isn't that the nickname of your mum?

It turn@ a usb extension cable into a regular usb
I guess that could be a use case?
- Or turn 2 extension cords into a long one.
  But a serious answer is that these are sometimes sold in a kit of adapters that would let you change the head. Most kits like used a normal cord as the base cord, but some used USB extension cords as the base cord. So this is meant to be a replacement part, not useful in its own right.
- wouldn't that just make this thing longer? we'd still have the same problem
  
  There are female-female USB extension cables. As to why those exist...

Such A-to-A adaptors and cables always have been prohibited by the USB spec, but people built them anyway. A common usecase for "illegal" A-A cables i remember was connecting PCIe cards (especially GPUs and mining cards) externally to riser sockets.
- I have an external 3,5“ HDD enclosure that needs a male to male USB 3.0 A cable to plug into a PC. Still wondering, why they didn’t use B…
  
  That's really odd. Why use a host connector when a client connector is intended for the purpose.
  Did they entirely miss the purpose of USB?
  
  I bought a breadboard power supply and the options to feed it power are a barrel jack and usb-a. Considering the size of the thing mini or micro would have made way more sense.
  
  I have a similar caddy. Many years old now. The connection to the host computer is a USB-A female, so connecting it requires a male to male cable.
- https://en.m.wikipedia.org/wiki/USB_On-The-Go
  In 2001 the directionality became kind of moot. Especially if you want to do attach something with an on-the-go host
  
  An OTG setup needs all 5 pins of the micro-B connector. USB A cannot be used for OTG. If a USB-A port can act as a client, that's not OTG, it's a botched implementation.

I’ve used them for extension, as it allows you to attach a second, regular USB cable to it.
- They're not priceless, they're $3.00
  
  In this case, less so, because any normal A to A cable would do the same thing, just with more room to spare.
  Agreed in general, though. I have so many random audio and video adaptors that I've used a surprising number of times.
- Well, what do you mean by "regular"? The cable would need to be female on at least one end, which I usually see in... USB extension cables.
- Not that you probably need to know this, but for some other stranger: there's a max functional length to USB cables. At work I remember pulling my hair out troubleshooting a printer until we swapped cables for something shorter.
  
  And that max length goes down with each coupling.
  We have smart boards in most classrooms, but in an entire wing of my department the smart board doesn't work. Reason? When we built the wing, 8 or 10 years ago, the installers fitted their own low grade plugs on the USB connection for the boards, before figuring out that they snipped the cables too short. Instead of running new cabling the installers then introduced another extension.
  Nobody cared to check it out before accepting delivery and my complaints went unheard by management, until it was too late to RMA it.
  
  That said, there are "active" USB extension cables which draw current from the power lines and use it to boost the signal along the data lines
  
  Meanwhile I have 25ft cables running my large format vinyl printers lol

Sometimes you have a female to female cable.

You ever watch Requiem For A Dream?
- ASSSSSSS TO ASSSSSSSS

Say gex
- gex
  
  haha, gross
- Gex 3D: Enter the Gecko

LUSBian sex obviously!

I dunno but it bothers me how much plastic wrapping that fucking thing apparently needs.

To connect two USB-A ports.
Basically the same as a USB-A to USB-A cable, just really short.
- USB-A to USB-A cables do not exist, the USB standard does not allow them, if you have a cable with two USB-A connectors then it’s not actually a certified USB cable. The same goes for USB extension cables and this adapter. Note how there isn’t a ‘USB certified’ logo on the package.
  
  The cables exist; they just don't follow the standard. I've used them when developing consumer electronics: the host controller on the device switches to device mode in the bootloader, allowing a host machine to connect and debug/flash the device.
  
  USB-A to USB-A cables do not exist
  wtf are you talking about, of course they do.
  
  USB-A to USB-A cables do exist.
  I have seen many (very cheap) peripherals use USB-A sockets. I figure those sockets must be a few cents cheaper than alternatives.
  
  USB-A to USB-A doesn't exist
  looks at old charger from an American device*
  HOLY SHIT A CRYPTID CALL SCP
  
  They do exist, despite the USB standards not allowing them
  See: cheapo video capture card for work, other side is just HDMI-IN and OUT
  They shouldn't exist but don't mean they don't when you get the cheapest little devices you can find
  
  It’s not hard to imagine a product that would require one, though. It’s how every phone charging cable works, just with a different size male USB on one end.

I used to have a portable hard drive that had a usb-A/ e-sata hybrid connector and I had to use a USB A to A cable (or e-data) to use it.

Get 2 laptops, put them side by side with usb ports wide open and plug them bitches together. Likely will short with 5v being fed both sides.
But in reality its a usb coupler (plugging together 2x usb extension cables). Not a great lot of use from them in my opinion. I've seen shit bodged together in low budget it offices using edge case crap like this.

Ass-to-ass.
- Docking

It's an Usb-A gender changer. It's not that useful but you could use it to turn an otg adapter (female usb-a to male usb-c) into a regular usb-c cable. I'd rather buy a usb-c cable though.

Many cheapo sata connectors need a cable like this(I use a male A to female micro b and then a female micro b to male A, it gets the job done)
But connector, idk

Not one that short but I do have A to A cord like that in use. In my case it's with a KVM that I lost and AC adapter for but found that if I plugged in to one of the rear console connections it could get it to power on from the USB device. Cable it to a USB charging port on the front of one of the UPS and away it goes.

Causing fires

I actually have a APC UPS at work that uses a USB-A to USB-A cable. You can look up the cable online, it's part number 940-0504. I was surprised APC used such a cable. I think if you tried to do something dumb like connect two PCs together with it, one of the USB ports would fry.
- pretty sure i tried it as a kid and nothing happened.

I would definitely find a couple use cases for these

Angering the USB-IF

Finally! USB Direct Connect!

So your pets can't chew the hard-disk cables.
Unless you have a pet rabbit.

The way these are called male and female has always been so wild
- It‘s a pretty good metaphor I‘d say and less bland than calling them plug and socket.
- Don't know what to tell you, people just kinda tend to be horny.

I have a cheap HDMI capture device that takes in video input, exposes it to the computer as a regular webcam, and then outputs it back to HDMI. It gets the job done.
It uses an USB male to male for power, and a regular one for data.
That said, not sure how a short one like that would help.

I had an old Medion digital camera that used USB-A - USB-A cable for synching with PC.
This could be a shorter version of it, tho idk why would anyone use this for thus purpose, would be awkward

So you have 2 USBC devices you want to connect together, a laptop and a phone for example, but for some reason you can't find your USBC to USBC cable but you do have 2 USBC to USBA cables.
Well by breaking the USB specifications you can connect the 2 cables together to make a janky USBC to USBC cable.
Alternatively you can get single circuit boards with USBA ports on them and you can use this jank of an adaptor to link them together.