I'm being semi facetious, but what does Matrix offer that I'm not able to get from my 24/7 tmux+irssi virtual private instance? Please don't say more notifications or addictiveness.
To me, it offered the ability of my fiancee and family (who don't have 24/7 tmux+weechat VMs) coming online. I now have them in my IRC client. It's wonderful, and I have wanted that for so long.