It would work the same, except you can sign up with one click, login with one click, and the server wouldn't store any password/key. But it also allows for addi

It would work the same, except you can sign up with one click, login with one click, and the server wouldn't store any password/key. But it also allows for additional functionality, for example in a photo sharing app/site you could tell it that only those with these ID's should be able to see the picture, without the site/app needing to know who those people are, they don't even need to have an account on that site.