You can add these ports to a PC. With help from the motherboard and power supply, they'll support both USB and eSATA, including mechanical drives that need 12V power.
eSATA seemed like it had potential but I can’t say I ever actually used it. I remember those ports, though. Might have a motherboard kicking around in storage with one.
There was a brief period of time where eSATA was starting to show up and there were never enough USB 3 ports. eSATA would have been kind of handy but I've never used it either.
I used esata back in the day and I loved it. I had a second hard drive that I could plug into my laptop with all my games on it. This was back when SSDs were $1 per GB on a good day so 120GB SSDs were typical.
And even in the early days of USB 3 external HDDs were slow. It wasn’t until uasp became a thing that they didn’t suck outside of backing up large files.
Not actually a terrible idea, even if it frequently was limited to powering 2.5" drives due to a lack of 12V. Some had extra contacts for that, but most that I saw didn't.
A KVM usually have circuitry that can handle a specific total bandwidth and a specific number of HDMI or DP ports (I've seen a few where using 2x 4K displays would disable the remaining ports until disconnected due to bandwidth).
To make this work as expected for a KVM you need circuitry to handle all ports being used for either standard (expensive, lol), and have each physical port connected to I/O on both the HDMI and DP controller. Or support half and half, but connect each port to even more I/O ports and start doing switching...