you can also invite a music bot or host your own that will join the voice channel with a song that you requested
When we get to alternative proposals with functioning calls I'd say having them as voice channels that just exist 24/7 is a big thing too. It's a tiny thing from technical perspective, but makes something like Teams unsuitable alternative for Discord.
In Teams you start a call and everyone phone rings, you distract everyone from whatever they were doing -- you better have a good reason for doing so.
In Discord you just join empty voice channel (on your private server with friends) w/o any particular reason and go on with your day. Maybe someone sees that you're there and joins, maybe not. No need to think of anyone's schedule, you don't annoy people that don't have time right now.
The big thing is the voice/videoconferencing channels which are actually optimized insanely well, Discord calls work fine even on crappy connections that Teams and Zoom struggle with.
Simply put it's Skype x MSN Messenger with a global user directory, but with gamers in mind.