Matrix is newer, afaik it is used by more foss projects for communication than xmpp, and it has a more widely accepted standards base for things compared to xmpp, where I have often heard that it has multiple different implementations for things like voice calling and encryption which are incompatible with each other. Don’t take my word on it, but I hope that at least by reading this those interested can search for the issues and whether they are valid.
But then, what do you mean by xmpp being easier to host? I’m not familiar with XMPP hosting.
Matrix requires a home server, and a database server. If you want voice calls it also needs webrtc voice infra.