There’s varying takes on why folks prefer Gemini:

• HTML browsers are too complex. It is virtually impossible to implement a new one. We’ve got 2½ implementations, i.e. Blink/WebKit and Gecko, and that’s it. Yes, you can use Dillo or w3m, links and lynx to view simplistic webpages, but anyone, who actually wants to use the web with these, will quickly run into webpages they cannot view.
  With Gemini, you can use tons of clients, some of them even written in Bash, because it’s so simple, and you will not run into pages you cannot view.
• Burn the web. Some folks hold the opinion that the modern web is beyond saving, because advertisers control many central parts of it. Presumably, these days folks are also glad to be spared from AI-generated garbage. And again, you can create your own webpage that’s all smallweb with pure HTML and whatnot, but anyone who actually wants to browse these pages has an easier time finding them on Gemini.
• An own community. Of course, using a different communication protocol cuts off communication with most of humanity. But as a result, many folks on Gemini know each other and bother reading blogs that they might not have read on the HTTP side of things.
  Well, and through survivorship bias, folks on Gemini tend to be nerds who care about permacomputing and the like, so that also helps with finding folks that have similar interests, even if you might end up reading their gardening blog, due to the aforementioned point.

I think the better comparison (whether that’s technically accurate or not) is to HTML + CSS + JS. Which is overly complicated for just small blogs and personal webpages etc. I think that’s the “issue” Gemini is trying to solve.