The passkey-derived key approach is the right UX instinct. Seed phrases are the number one reason normal people don't self-custody. Nobody who isn't already a bitcoiner will write down 12 words and store them in a fireproof safe. That's not a user flow, it's a lifestyle change.
The tradeoff worth naming: passkey backup lives in your Apple/Google cloud. So you've moved the trust assumption from "Piggy holds your keys" to "Apple/Google backs up your passkeys." That's a genuine improvement in sovereignty but it's not the same thing as writing down a seed phrase in a notebook. If Apple locks your iCloud account, your piggy is gone. Worth being explicit about that in the docs.
Building on Spark is an interesting choice. Curious why Spark over something like Breez SDK or LDK. The Lightning wallet space has a lot of infrastructure options right now and each one comes with different tradeoffs on channel management, LSP dependency, and liquidity.
The passkey-derived key approach is the right UX instinct. Seed phrases are the number one reason normal people don't self-custody. Nobody who isn't already a bitcoiner will write down 12 words and store them in a fireproof safe. That's not a user flow, it's a lifestyle change.
The tradeoff worth naming: passkey backup lives in your Apple/Google cloud. So you've moved the trust assumption from "Piggy holds your keys" to "Apple/Google backs up your passkeys." That's a genuine improvement in sovereignty but it's not the same thing as writing down a seed phrase in a notebook. If Apple locks your iCloud account, your piggy is gone. Worth being explicit about that in the docs.
Building on Spark is an interesting choice. Curious why Spark over something like Breez SDK or LDK. The Lightning wallet space has a lot of infrastructure options right now and each one comes with different tradeoffs on channel management, LSP dependency, and liquidity.