So that would require a change to the kind:0 NIP to allow for a second/backup LN address? If so, then theoretically would it possible for a client to implement that? Or a fallback cashu wallet? Just thinking what would need to happen to even make it possible. Payments are fundamental to a lot of what happens on nostr. Whether custodial or self hosted, a wallet failure is more than just a nuisance, and it happens too often, regardless the wallet provider.