I feel these sockets may have been a practical choice for power supplies that extend too far up or down. This approach gives the best of both worlds for them to be able to plug in whatever is needed. Why are they in the ceiling above a dart board? No clue…
I took the screen off my old dell laptop and turned it into a mini blade server with built in UPS. It ran for years. I have no doubt the battery was knackered by the end.
The only reason I replaced it with a Mac Mini 2012 was because it didn’t support usb3 and 4K video saturated the usb bandwidth.
Now my 2012 runs Ubuntu server + docker for those interested :)