Gemini is no different. There's overlap with the web's use cases, but its its own thing. As a user, why not both?
What does Gemini have to offer to web users that the web itself doesn't? It's entirely possible to write small, simple HTML documents without javascript on the web. Indeed, one could replace Gemini entirely with a Geocities-like service that enforced the same rules, including only allowing linking within the platform.
Alongside the web, Gemini is just a worse version of the web, it isn't different enough to be its own thing, nor does it offer anything unique. Gemini only makes sense as a means of forging a separate identity from and exclusionary of the web, as you yourself said in the original comment I replied to[0]: (If they were happy with the web, they would have stayed there.)
But they have stayed there. Gemini users still use the modern web all the time, mostly to remind everyone that they exist and are rejecting the modern web so hard you guys.