You can see Kagi's details on what counts as a search here: https://help.kagi.com/kagi/faq/faq.html#how-are-searches-cou...

I log into Kagi but usually don't have it as my default engine. I can search with DuckDuckGo or Google and then only jump over to Kagi with a bang when I really need to, which helps preserve my limited searches. While Kagi doesn't count bang searches, which could let me use it as a default, I'm an idiot and will forget/mistype, which causes an accidental usage.

I also found Kagi's snaps very useful, but being able to use them with other engines means I don't have to burn a Kagi search just to use them.