can't say i've ever written and hosted anything on Gemini, so maybe i'm not the best to comment. that being said: i host a website that is all plaintext. no fancy tables or images; the most technologically advanced formatting features are <code> tags and bullet points (both of which i would just denote with their markdown equivalents if Gemini or WWW clients didn't support them)
i think there's a very fine line that any creative type walks when pushing something out towards others. that line between writing for yourself and writing for an audience. as much as your criticisms of the content on Gemini (not Gemini itself, i'd argue) are valid, OP; sometimes it's not about you, or any other reader, surfer or consumer that finds their way onto a site. sometimes the content on a site is for the siteowner. sometimes it isn't. i have two resources pages that are for others as well as myself: i want people to be able to have a better experience through the stuff that i link, as well as highlight that someone else has made something - but pages like my blog are entirely for me. it's cool if you read it, it's even cooler if you comment! but that's for me, and me alone
the beauty of Gemini, to me, is that anyone can access it. easy to write something that loads and parses Gemtext, and a small enough protocol that it's not actively monitored by any agency that would use it to advertise, or worse: moderate it. soft as it is, search engines do this. but Gemini is so small that search engines don't matter. gemrings could take over and be the best way to find anything ever, with their pros and cons. the only reason i don't jump ship onto Gemini is because i still write for, and have stuff to share with, other people
as you said: to each their own