alt Hacker NewsWaaaaaaay better clients (this is the big one), chat logs that are easier to search through with standard unix tools, avoids issues with OMEMO breaking (which stops people chatting at all, breaking the main usage of the program). Saying this as a regular user of both. I spend way more time on IRC and I enjoy irssi much more than Gajim, Dino, or Conversations. I do think XMPP has potential, though.
Yeah I'm planning to send both matrix and xmpp through bitlbee so I can use a terminal client as well (I know matrix has one technically but it is reeeeally crufty). I don't understand why every modern chat client has to be 99% empty whitespace separated by squircles.