I've read that FAQ entry, but it's bogus in terms of chat. Maybe the protocol is more useful for some other thing, I don't know (although I doubt it since XMPP at least can also do very similar sorts of things with pubsub if you need them for some use case, eg. the IoT people do this sort of thing a lot).

The FAQ skirts around the fact that it doesn't matter if they're slightly different: you shouldn't make up your own new thing to force adoption of your commercial product. Use and improve the existing technologies that are "good enough" and stop splitting effort and making yet another standard that everyone has to try and support or run bridges for. This is unacceptably bad engineering. Saying "this is subjective" is true, but just an excuse for "we have not-invented-here syndrome".