@kura there was also the whole thing about how XMPP is not good for mobile because the protocol was designed for desktop machines before smartphones hit. This used to be true, but recent extensions have taken care of that - Conversations for Android is a good implementation example.
Another hit came when corporations dropped support for XMPP in favor of creating walled gardens around their propriety IM protocols. It created an image of "XMPP is dead", even though it's not really justified.
@polychrome personally I don't think matrix is so fit to be mobile as well. Also synapse is a shit piece of software. And a performance hog.
I wonder if dendrite will be better, got a weird feeling though
@kura it's too early to tell, imho. but food for thought: I used to be connected to IRC on my mobile via 2G data back when 100MB data caps were still a thing and never hit the cap. I doubt Matrix can do the same. 😕
@polychrome irc was a fine protocol for what it was
@kura still is! I'm on a private server now days 
@polychrome not using it anymore thanks to discord and all
@kura the difference is that XMPP is older and is designed to be similar to old school person-to-person IM networks (ICQ/MSN/AIM/Yahoo etc). It is federated, extendable and also features such as chat rooms and more.
Matrix is chat-room oriented and is "easier to use" thanks to its main official client being a very Slack-like webapp, supporting remote stored chat history and media in chat. It is however still evolving and can be heavy.
XMPP is already catching up feature-wise but.. hype will be hype.