Ah - my depression era grandparents never threw things away. One reason: they could re-use the object if it were durable enough. And they did.
By the '80s (maybe earlier?) they were complaining about the culture of trash. Their survival instincts were telling them to save and re-use. Their shiny new culture was telling them to throw that shit away.
I won't link it, but an image can be found easily. Right now I'm looking at a New Era Potato Chip canister that lives in my office. (It's weird - seriously, google it. "Feast Without Fear.") It's still good for storing things.
I save things expecting to reuse them, but then I am disorganized and often can't find them. Often with little computer accessories. So, even if I do need to reuse a dongle or cable, I can't find it and order a new one anyway.
I am glad that I am not the type of person who collects items thinking they'll increase in value, or I'd probably become a full blown hoarder.
As the other user said, I found them from backpacking for roughly the same reasons.
Subsequently I've found them to be extremely convenient whenever I travel. They fit into a vehicle cup holder, will last months with daily use, and are cheap enough that I don't care much if I lose or abandon them. If I'm flying I can buy them at the destination. They're lightweight, durable, disposable, and easily replacable across the US.
At home, regular life, I avoid the cost and waste with Nalgene & stainless steel. My oldest Nalgene is thirty years old, my oldest stainless steel a third generation hand-me-down that's eighty years old. This is the way.
I use two of them for backpacking. The Sawyer (and a number of other) water filters screw onto standard threads, so I can use 1L potable and 1L non-potable when I'm on shorter trips and not using my gravity bag.