The option to "sign in with" a third-party provider is already extremely widespread and most people prefer it.

But U2F/Fido identities are better in that the people who prefer to ensure their keys are in escrow with a corporate overlord can choose to do that, while security-conscious people can go a step further and use physical security keys or third-party solutions with different sync mechanisms.

Security is a nightmare when you trust systems that you shouldn't trust. That's for sure.