The design of the payment system seems a good choice for privacy, but I don’t see how you can prove that it is doing what it should. I’d definitely trade privacy for accountability.
Is there a document that explains how an outsider can check that their votes+cash finally add up to the total for that publisher.
I know I should try it first before asking, but I have a terrible itch when it comes to bitcoin (a lot of drug and arms dealers were early adopters, and they profit from every new bitcoin user). I’d use other cryptocurrencies, community currencies, dollar or euro.
BTW: This is one the coolest brave features: it is very inefficient to fund publishers through adds!