I like the new permission "Hide Option to Switch to Salesforce Classic", but it feels strange because its one of the only (if not the only) permission that once checked give less permission to the user than before.

This also means that I can't create a Permission Set to give to only a few users access to Classic. I need to do it the other way round, create a Permission Set to restrict access, and add it to the 99% of the users that should not go to Classic.