Earlier quoted context omitted.
Yep. Their docs inspire little hope that the protocol will be little more than niche. How to build on top of this protocol without requiring someone with domain specific knowledge is beyond what's offered. Cue XKCD protocols comic.
Matrix is gaining adoption throughout the open source world super quickly. There are screenshots, guides, and links to join all over the place. Given that, I'm really impressed that anyone looks at Matrix and thinks of it as "little more than niche".
Given that matrix describes itself as an open standard, neither of those aspects says much about the project other that there's either some goodwill or a PR department.