Believe it or not, I have one on the wall in my shop.
It's a remnant from when the shop was originally built- which predates me as a person, let alone my living here.
I was given to understand that it was abandoned (that is, disconnected from service, but left hanging on the wall) sometime in the early 70s. I basically just worked around it when I refurbished that part of the shop into my machine room back in '01 or so.
I guess I'm surprised to hear there's actual collectors of such things- to me that's like finding out there's a whole Reddit of people that collect 1972 Ford Maverick rear brake cylinders, and they're always arguing about which one's more valuable- the driver's side or the passenger's side.