User roles

hello, I have a little trouble understanding the difference between private user / public user.

If I add a “role” column to my Users table, anyone with a role is a private user and anyone with an empty one is a public user?
But both will have access to the application?
The role just allows to give access or not to certain pages?

It depends on your privacy settings. See below:

Roles can be used in that way. But the best reason to use Roles is as row owners in other tables. Using roles as row owners allows for multiple users to “share” access to the same rows without having to create multiple row owner columns.