Nothing is stopping it, it’s just not particularly convenient because it’s designed around the limitations of the phone system.

SIP could handle it all if you wanted though.

Then then answer to your question is yes, you interpreted it incorrectly. The original (and common) definition of that word is vastly different than what you assumed.

Do you know what a semaphore is?

Quite literally designed for long distance communication.

Used extensively in many different variations before wire/electricity based systems became available, then even used after that for communication in places where you couldn’t have a wire (like between boats)

The number one google result is Owncast.

Looks like it doesn’t save the video by default but there are workarounds to record it.

No.