I think it’s more constructive to think about what risks are borne by each party in a transaction, how much it costs to take on each risk, and which party is better equipped to manage each risk. Then you can construct the thing that people actually want, and that thing is almost certainly not cash as we think of it today.

For example, if I order something and pay cash, I’m taking on very different risks than if I pay with a credit card. Similarly the risks to my privacy are very different with each one. Maybe we need a third option that sits somewhere between the two.