It lately had a bunch of controversy around it, development is pretty halted and the inability to stop randos from spam inviting you into chats with csam kinda is a nono for me.

XMPP is a protocol, not a program, so you can use whatever program that supports XMPP, it pretty much has the same functionalities as matrix, bar the screen share but there's several clients like Dino that let you video call, which with something like OSB virtual camera, I can bridge in the screen.

I do like the shiny new fads but having a mature protocol that is the used by shiny programs and lets you talk to older program users too sounds better.