I don't know much about privacy.com because it's not available outside the US. Knowing a bit about the legal side of payments I doubt they can promise anonymity though. They're just not passing my identity on to merchants as I understand it.

I doubt that there will ever be a widespread, convenient way to make anonymous electronic payments. The authorities would never allow that to happen (for understandable reasons I have to say).

Incentives are not working at all. Lots of services I pay for go to great lengths to squeeze even more out of that customer relationship. And how could I possibly trust a large number of small companies I know very little about?