I accepted paying for it after the trial because every other search engine just sucks or isn't customizable enough in comparison. Not to mention ads and tracking.
Kagi results are really, really great. I find it better than Google for technical queries and better than DuckDuckGo for localized queries. Unfortunately, it's not 100% SEO-trash proof, but I can permanently block those domains from results in one click - a refreshing experience. The AI quick answer is on par with Bing's (more accurate than Google's), but the best feature is the possibility of banning/re-ranking websites (such as those SEO-spam ones).
This feature is probably the one any family member will find useful: prioritising websites they like the most and blocking/down-ranking those they dislike. For example, I hate Pinterest and have banned it. My girlfriend, on the other hand, loves it and gave a better ranking. Guess that's what customisation is for...
The lenses are probably also family-worthy, since you can quickly create personalised results pages for good sources for homework research, safe online games for children, trustworthy news for your grandma, etc. But I've never used it extensively yet.
There's also some minor features (auto-login link for anonymous tabs, bangs, news, etc) that you pretty much expect from a search engine nowadays, too. IMO, the most complete and efficient search engine I've used so far.