I've registered with Kagi using an email address I control (i.e. no Gmail address) since I'd like to migrate away from my Gmail account being a "single point of failure", as there are a lot of stories online about Google closing down Gmail accounts without providing recourse or even just useful support.
OTOH, I still think having the "Sign in with Google" option is a useful feature, and one I'd still like to use. I'd just rather not have it as the recovery channel for my password (and, thus, essentially the entire Kagi account).
Please consider adding the option to register for Google's sign in functionality in addition to my password.