But how do you tell people who to send the money to without telling someone the connection between your identity and your public key (from which they can trace all further targets of the money from that key)?
I’m pretty sure Bitcoin at least provides the ability to run as many keys as you choose; if you’re really concerned about that kind of tracking, it’s quite simple to make a new key for each transaction.
Also the British cryptographers made a practice of “gardening”; before a German expedition was to depart, they’d mine an area so that they’d have known plaintext to work with. I imagine that helped a lot too.