[peeters]

I wonder if it's implicitly acknowledging that social media (at least Google and Facebook) are authentication providers for thousands/millions of other services. So it's more of a "protect the keys to the kingdom" suggestion for those that use Facebook/Google to sign in to everything (not that I recommend doing that often).

[Ntrails]

I would 100% consider email under the highly important banner, but I'd not considered at all the "Log In With Facebook" angle.