I've been quite dubious about Matrix in the past, but watching the #FOSDEM presentation about the performance improvements in the upcoming version 2.0, and the capabilities its new embedded and p2p modes enable, such as https://thirdroom.io entirely within-browser spatial-audio VR space, I'll be happy to say I was wrong - it will be the new private (or in-group) communication fabric for anything that needs private/group communication.