Oh, I suppose. My experience with mumble is 12 years out of date, but I recall that you generally plan to use Mumble in advance rather than contact somebody through mumble.
I hardly use nor see reaction gifs on discord, though the emoji UI/UX is a big deal. (I think the gif system they use has an open API though, so it could be added to other platforms..)
Same thing that’s wrong with Teamspeak and the other old standby, IRC:
A dated look and lack of shinies like inline GIFs scares the youngsters, the lack of history/persistence drops them and everyone else.
Ah, the many logging bots of IRC. Going to a website or getting daily sized text files DCC’d to you so you could search up if your problem had already been solved, or so someone said they think it was solved on one of those days…