The beauty of P2BK is that it provides perfect privacy. Alice and Bob do not need to communicate at all to set it up - all Alice needs is Bob's public key.

The ecash is locked to totally unique blinded public key(s), keeping the receiver's identity private from anyone who views the ecash. This means tokens can be published securely in public.

The sender's identity is also protected, because Alice uses an ephemeral keypair to create the shared secret, and throws it away afterwards. All Bob needs is the ephemeral Public Key!