Oh no wait, you wanted some retarded Windows/Apple thing that needs biometrics, locks everything to your pay for service/hardware, and has a worse security model.

Nevermind just use a password.

I was having this discussion earlier with a friend and we could not think of a compelling case. They seem less portable and harder to use on multiple devices or new devices. The only thing I could think of was protection against copied sites, but most users using password managers also block ads which should block most scam sites and password managers just need to have more messaging for if you try to fill in credentials on a site that is different from the site information saved with the password