It's a mark up language squarely focused on those that write text, but arduous to use if you want to share things you've illustrated, which is most of what I share online that isn't tech related. There's of course the argument that inline images/a spec'd way to expose an image directory listing with thumbnails/etc would only serve to distract or exploit you... but that also ignores the fact that people make art for your eyeballs too. Text is certainly the first class citizen, where images/music/video are all tied for second class, accessible only by downloading them 1 by 1.
That does mean it's perfectly fit for purpose! I wouldn't say it's bad just because I don't get my specific needs met. Someone who's needs are met by Gemini will love it.