The whole point of Matrix is that you don't have to use matrix.org to use Matrix. Anyone can host a server and talk to anyone on any Matrix server.
next you're going to tell me grandma should just use IRC instead.
I host my web, my email, my XMPP, my TURN/STUN, etc, so I gave Matrix a try. In short: it's horrible. It's insanely resource hungry, both synapse and dendrite, plus dendrite is so not finished it hurts.
Stick to XMPP until Matrix is in an actually usable shape when one doesn't need a small power reactor to run it.
About an hour ago.