Adjacent. Matrix uses a lot more resources & storage than XMPP, making XMPP a more efficient method of decentralized, self-hostable communication (both servers and clients). Having control of your own chat server will prove important with facism on the rise, so owning your own server node + E2EE will prove important—but if the system is too expensive that everyone cannot afford to run it, it isn’t radical tech.
I have one from Morefine. It works, but I hate the way these Chinese sellers put firmware on Google Drive as it feels super sketchy & lacks the source code (luckily this one doesn’t require exclusively Microsoft Windows executables unlike some other products I own).