Ok, after reading this and also your top-level comment, seems we're talking about the two different types of tagging ("personal curation" vs "collaborative") which you list in that comment. That makes more sense.

Definitely agree that if you're mainly tagging for your future self, you can derive tons of value without constraints. Whereas if you have people tagging for others, that needs more support.

Although, if you're so inclined, you could also view these as a continuum --- with "personal" tagging being the apex of centralized consensus, and having to increasingly labor for consensus with every added user in the system.