Authorization through social networks and registration through social networks. networks on the site. What is the difference?

Question

Social media

Authorization through social networks and registration through social networks. networks on the site. What is the difference? In addition to the fact that the first is authorization, and the second is registration.

Answer 1

In the first case, you adjust your site for authorization in social networks and do not need to store your database with users.
In the second, authorization is performed by your site / engine, and social networks give only user data for registration (name, gender, profile picture ..)