I've been invited to like a million different discord groups from friend groups that overlap in various ways, and they always seem to be full of a bunch of people I don't know reposting memes off of reddit in the chat channels.
All I wanted was a voice chat with the 5 people who I know and am hopping into Overwatch with. Mumble does that job better, and guzzles less of my RAM to do it.
The feature that got us on the mumble train years ago was how well it auto-balances the sound volume coming from different users. Other software we tried at the time you’d have some people much louder than others. This is probably pretty standard by now though.
EDIT: missed edit window on my parent comment, but a funny note related to Electron system resource usage. In addition to the RAM thing, it's based on Chromium which means it's using the GPU for rendering. There's an option in the config to disable this, otherwise it makes you exit the Discord client when you install GPU driver updates.
Not a huge deal, but it feels real silly when you get that popup. Like "I get that I need to close games to update GPU drivers, but my voice chat? Really?"
I'd love if that was it. It's when you see horrifying 4chan greentext that I start to cringe.
For an Overwatch specific if more unusual use case, if you want to have a group of 12 people organizing private 6v6 matches, this is much easier to coordinate when you can all hop into a single shared voice channel between matches to chat, talk trash, reshuffle teams, etc.