Since I don't have any lawyers on hand, I'm not qualified to design a private system so I don't feel like making one up[1]. But since I remember how bank transfers work right now (hint: they go through the government), I can say people claiming they have some right now are wrong.

[1] for instance, I don't remember the legal status of mailing cash through USPS, but pretty sure it's different privacy-wise even though it's "the government"

Why is it not put your transaction history into a database that the government can subpoena if they want to know what you've been buying, which all of us have already been doing if you're not conducting transactions in cash? I have a lot of facts about myself I'd like to keep mostly hidden, but are not hidden from law enforcement officers who can get a warrant.

Why do you want to watch me take a dump so bad?

I have no doubt someone somewhere on the internet would pay money for such footage. Maybe it'll be a business rival seeking to publicly humiliate you.