At my company we use Feature Flags for Licenses, and Authorization for users.

They are absolutely similar concepts, just as different levels.

If a customer wants to buy Analytics for example, it is controlled via a feature flag to enable it for that entire customer. By default all of thier user accounts can then access Analytics.

Then if we want to restrict certain categories of their users from seeing Analytics we can do that at the Authorization level.

Is it possible we could control all of this with one Authorization layer? Yes, probably.

But this lets us have a bit more fine grained control over things.