So that recoverable pubkey can be hiding in the 64 bytes? ok I need to look at this because of the reduction in computation complexity.

The cloak is to make it impossible for anyone without the correct private key to acquire the ECDH secret of a message. They only have one half, the public key of the sender, which is a different key derived via scalar addition for each packet (and message, or onion, if you prefer).

The packet dispatch between peers is of uniform sized packets and in any given stream there can be millions of different looking cloaks (2^24) and the key changes are done far more frequently than this. Traffic between peers is a mass of these identical looking messages that you can't separate without knowing secrets.

The messages that are broken up into the packets also have these keys in the onion layers of encryption, again each one has a new secret key giving a different public key each time.

Really just obeying the rules of how to use EC. Never the same hash to be signed twice. Easy to guarantee it with a random 8 byte nonce in every message.