Not sure I got the point ! - like what is the purpose ??
A way to send onchain bitcoin privately to any nostr profile. Onchain zaps are a bonus if we want to display this txn (privately) in clients
Silent payments lets you publish a static payment address, and no observer can see any payments made to it. You need the private key to see your payments. This means no more address reuse, no more having to generate new addresses for payments. No more looking up wallet balances on block explorers. Huge UX and privacy boost for Bitcoin.