For me, it'd be nice if Kagi could be used as a mix of a private bookmarking service (like Pinboard or Raindrop) and a private search engine (like YaCy).
I save every interesting article, service, etc that might come in handy in the future. So now I have 10k+ bookmarks in Raindrop. But in 80% of cases when I need to find something, I get dozens of results but not the one I need.
The regular bookmarking services are more suited for organized links, where you tag them and add some description. But if you just want to save links with one click (e.g., via browser extension) then it'd be tricky to find them later if you have a lot of links.
Search engines like YaCy do a bit better job with the search, but adding new links requires a lot of clicks.
So if Kagi can combine the best of both worlds (ease of adding new links + awesome search engine), it'd be nice.