This is a good question that's often asked about Gemini. The creator addresses this in a part of the FAQ: Why not just use a subset of HTTP and HTML?
Personally, I find Gemini nice because its utter basicness guarantees that there's no room for the kind of bullshit you might find on the web. Sure, you and some other nerds could make a "friendly HTML" club, but participation is voluntary and there's no way to enforce the rules to keep the pages simple. And how would you know what sites are "friendly" just by looking at the hyperlink? Gemini creates a universe where sites have to be "friendly"; there is no other way.