Kind of baffles me that people still make chat apps without those.
Multimedia transfer is still a practical impossibility, for better or for worse.
Mobile IRC works, sort of, if you don't mind spamming the channel every time you lose connectivity when you drive into a tunnel or when your phone goes to deep sleep. Again, you can set up a bouncer for that.
I welcome the new changes in IRCv3 and hope that one day soon all IRC users will be able to use the features everyone else has been using for fifteen years or so.
"Anyone can start a server" is only true when you're lying about what a "server" is. (Or redefining it to the point of usefulness.)
A Discord "server" is just a defined chat namespace. All the Discord chat "servers" live together on the same actual load-balanced VMs or whatever on the physical servers they run.
It's honestly the thing that's annoyed me most about Discord from the very beginning, long before they introduced the ads and the microtransactions and the mandatory doxxing.