I just caught up on nostr silent payment adresses, glad to see people actively exploring the idea. I think it would be *a lot* better than any other proposals that reuses addresses.
It would be even better to have the silent payment wallet generated separately and simply linked to your nostr account because as the NIP author correctly assessed tightly linking your nostr identity and your payment code means leaking one also leak the other. But if being able to generate the silent payment code directly from the npub is hard requirements then yes please do that instead of treating the npub as a taproot key...
A few other thought:
* frigate is indeed out of question (see above), and author doesn't seem aware there is an alternative called blindbit that serves the tweaks and let client do the scanning itself
* I don't think that immediately sweeping all incoming transactions to a new address is necessary
* out of band notification of the transaction is possible, but there's also a proposal for notifications over nostr: https://gist.github.com/setavenger/a0cd7e71b47ded9fca9c99085130cf2a
* even without notification waiting for the transaction being mined is probably acceptable for a donation use case

I'm not sure I get the argument about recipient leaking his private scanning key being such a big danger for senders, it literally doesn't reveal anything else that you couldn't already figure out by chain analysis.

What would be great would be to have some kind of payjoin baked in to add some obfuscation, but I'm not sure how practical it would be.

@Alex Gleason I've seen you're implementing BIP375 in Ditto, we're a couple of sp implementers working on bringing that to rust-bitcoin too, and I think that people at bitcoinjs-lib are working on that too, I think at some point we'd better all take a look at what we're doing