nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z this is how amethyst could have or integrate with a cashu token wallet: With cashu there is no need for a lightning wallet, and the cashu mint can be a lightning "zap proxy" (in place of NWC to an online lightning wallet). Profiles could indicate (with a boolean or enum) whether they prefer nuts (dm nuts) or zaps (lnaddress) for nostr clients that support nuts.
Discussion
Yep, the only issue is that all cashu mints are custodial at the moment. But looks like nostr:npub12rv5lskctqxxs2c8rf2zlzc7xx3qpvzs3w4etgemauy9thegr43sf485vg is thinking about a noncustodial version.
Otherwise, yes, zaps should just use nuts and not lightning.