The ability to essentially "weight" particular domains (pin, block, or anywhere in between) has saved me so much time. There are certain searches I do (music-related in particular) where I always want particular sites (metal-archives, bandcamp, etc) to be the first results, and having that as an option is great. It means that searches that I perform often have a result within the first 1-5 results that is exactly what I want.
No ads, way less SEO spam, and the ability to completely remove domains from results if I think I need to tweak it further. For most of my searches I previously used Google for- Kagi makes Google's results look laughably bad.
I've also been using it at work for tech searches (linux, redhat, etc) and it has saved me time there too.
I use a "family" account- and have one work account and one home account that way I can have different settings for different environments (would be neat if this could be built into non-family accounts though... like "personas" or "profiles" or something...) because I'm overpaying a bit to have the two account setup and don't reach the search cap. I think I'm okay with that though, because having the cap so high means I've removed the "running out of searches" anxiety from my usage of the service.