From what I've gathered from using Gemini, it comes off as an alternative browser, or a way of using the command-line to make a way of interacting with others. The Gemini I used for the most part was Antenna, which had a bunch of links to different articles and other Gemini's. People on there seemed to be posting about the kind of research they've been doing, journals with links to images taken, and sample codes.
Since Gemini was first developed and put on Github during the pandemic, people used the initial code/application and began to modify it, making multiple unique versions that are either downloable or just a link to use. I'd imagine if it's functional in all the right ways than the Gemini is allowed to stick around on Github. One particular highlight I found was someone speaking about their travels along with providing images of said travels. Traveling around is something I want to do, and when the pandemic ends I hope I can get back into it.
I don't think Gemini is a useful alternative Internet primarly because of the things you need to do to use Gemini can be done on the other platforms way easier. I had to get a specific link from someone to use the current Gemini I'm using, and with others you can just search or type up the link. It could definitely use a bit more experimenting before it gets on the level of things like Chrome and Internet Explorer.