The "we" in this context (ordinary users) also comprise the majority of voters and regulators who will ultimately decide how the system you propose is built and what restrictions it will have; and that is a group that is not solely motivated by your business interests -- so it is kind of important for you to be able to convince them that your system benefits them, and not just a few businesses.

Why should a Congressperson vote to build the system you propose instead of introducing a harsh privacy law that restricts which businesses are allowed to collect identification?

We're already living in a world where you have to "login with Facebook" to do many things, but at the very least you can currently still create a fake account if you have no other option. If reliable identity verification starts becoming commonplace, that option goes away.