I never got the fact that Discord uses the "server" name for what is effectively a hub.

I use Discord every week, when me and my friend are gaming.

Before that we used Steam's built in system, and before that I hosted my own Mumble server.

Discord is decent, it makes it super easy to stream to stream you monitor to others in your hub, that is a brilliant feature.

Steam is fine for one on one chat, a bit more complicated than needed with group chats last time I used it.

Mumble has excellent voice quallity.