@ryanc I recently started using it in addition to XMPP, SIP+SIMPLE (through Linphone) and Jami.
In the end it's about whether you have a need to reach particular people and what they happen to use. I hope at some point there will be good multi-protocol clients again or maybe Matrix servers could implement XMPP S2S. (Jami does have SIP support, but I couldn't get SIMPLE going with it as smoothly as Linphone.)