Silent payment is right now unusable for light mobile clients so not a solution tonreplace bip47, I don’t need a separate scanning server for SP, BIP47 is serverless Op_return in Tx0 ther for a reason and it uses standard 83bytes there is nothing spammy about it The op_return contains info allowing the server to verify that the fee was actually paid to a publisher. It's an anti-spoofing mechanism. If the fee is not seen on chain then the inputs are not registered. It also allows to NOT use a static fee for address collection.