For a Public Website, one valid usecase is the need to allow guests to register users, but then require admins to manually activate the requests.
Of course, the first thing to do is to activate the Authentication Active Check option under Administration > Users & Rights > Registration. One problem here is that it will ask users for a validation key, which does not make sense in this use case.
Now comes the real problem that we have no UI for admins to:
- See the user's active status from Administration > Users & Groups > Users
- Manually activate a user (preferably from Administration > ... > Users)
- Use the UserDirectory to customize it and add a column for the Active property to see the active status of users
- Edit each profile in object mode and set the Active property to Active, then save the page.