why the sha256 hash of the public key and not simply publish the sha256 hash of the “PRIVATE” key instead? Sha256 is secure and there is no way backwards to get the private key. This would mean that everyone in here could only check afterwards whether the person knew the correct private key, i.e. only after the pubkey had been made public by a TX.
mainly because with SHA256(PubKey) you can derive and check the ripemd160 , while with SHA56(PrivKey) there is nothing you can do ( maybe to establish the authenticity
after the balance has been cleared out, but that will serve no good)