I think you're mixing up anonymity, privacy, fungibility and encryption.

Four very different things which have potentially nothing to do with each other and which are optimally deployed in very different use cases.

Anonymity basically alludes to anything that doesn't have a name attached to it. Where the medium is perfectly visible but where any association with individuals has to be gleaned from outside of that medium. For example, if I receive an anonymous message from some woman telling me that she loves me then the message is perfectly visible, it just doesn't have her name on it. I have to start doing research outside of the realm of valentine cards to find out who sent it. I can show the card to all and sundry and it's still anonymous.

Privacy, on the other hand alludes to a restricted audience. For example if someone goes to the crapper and locks the door, they'll be the only individual partaking of the experience. If you make a bank transaction, only you and the bank staff will be privy to it. In neither of these cases, though are you "anonymous".

Encryption is one method of enforcing a restricted audience - i.e. privacy. It does not, however, make you anonymous.

Fungibility is a property of a (monetary) medium which makes 1 unit of that medium indistinguishable from another unit. Fungibility does not necessarily enforce privacy because it doesn't "hide" anything. But it does mitigate the propensity to discover the historical movements of a unit of that medium. Fungibility therefore DOES boost anonymity in a way that encryption doesn't.

If my anonymous admirer sent me a totally fungible valentines card that was printed with nothing but I LOVE YOU on white card, and all other valentines cards in the world were exactly the same, I'd have a damn site harder time tracing her than if it was handwritten fluorescent pen that was only available in one shop in my local town. Either way, no recourse to encryption is needed. Nor is it with regular cash, precious metals or any other monetary media that have been floating around for centuries, serving as the reference standard for monetary anonymity.