While I always prefer email/password sign-in when available, I've used Sign in with Apple exactly once. It's on a website that only offers "Sign in with <Google, Facebook, Yahoo, Microsoft, Apple>". Given that you don't need to log in to use 99% of this site's functionality, and this site serves a niche market with a small development team, I respect their decision to not try to roll their own authentication.

I'd rather they use oAuth than blunder their own implementation and risk a breach.