How do you create a new entry in the global database? What kind of proof do you require that a human being was born? What can you do once identity/password/whatever you use to access the ledger was stolen? How do you know when a human being dies, so you can invalidate e.g. their voting right (which they may executed via a bot)?
I think you’re making it a bit too easy for yourself here. Authentication is one of the hardest problems of speculative design!