There's probably a 3rd party program for Apple that does the same thing.
If you have too many different username/passwords you will not be able to keep them straight. This is what OpenID was supposed to solve. One can flip the argument around very easily: if there were fewer sites maintaining their own password databases, then there would be fewer breaches.
And that does NOT mean using OpenID for everything including financial accounts.
"We demand to see your email account."
An email account isn't like a passport or other official document. It can be created, or deleted, on a whim. What kind of "security" do they think this will bring?
Do not simplify the design of a program if a way can be found to make it complex and wonderful.