Physical cash with the Argentine peso offers privacy, but its still a shitty money.

The most desirable characteristic of money is that it is "hard to produce" and therefore resistant to debasement.

As for privacy on Bitcoin, JoinMarket works perfectly well. Here is a typical JoinMarket transaction.

Can you tell who the sender and receiver are?

https://mempool.space/tx/a56d23da7df68eb49d3665452bf7085c07a79be62f29f19e588240f02eb94c76