Have you looked at the protocol? Have you built things in both? I have, and I think the Matrix protocol is pretty good. The goals are different. It's not a send once and forget kind of thing, like XMPP, Signal and email. It's about keeping your chats synced on your server, and with any other server you happen to be federating with. It's Discord or Slack, except federated. That's not easy, and it's not simple, but it has huge advantages too.
Have you looked at the protocol? Have you built things in both? I have, and I think the Matrix protocol is pretty good. The goals are different. It's not a send once and forget kind of thing, like XMPP, Signal and email. It's about keeping your chats synced on your server, and with any other server you happen to be federating with. It's Discord or Slack, except federated. That's not easy, and it's not simple, but it has huge advantages too.