Correct, this is the origin of the term. Before cloud services like Discord, people had to set up servers specifically to run TeamSpeak, Ventrilo, or Mumble. Discord has now largely/almost entirely replaced those applications, and it's just a vestige like "roll down the window".
The internal term of "guild" is more accurate, but no users actually call them that.
Not to disagree, but I don't really see how the old rotary handles suggested the term "roll down the window" either. What was rolling? If I were supposed to describe the old way without knowing an existing word for it, I'd say "crank" was the closest option.
True, it wasn't "rolling" in the sense of the physical action you performed or even what the crank did, but the crank did move in a circular motion, and things that roll also move in a circular motion, so it makes a little bit of sense, even if it's not really rolling. Not sure why that term stuck.
The internal term of "guild" is more accurate, but no users actually call them that.