At launch, full ecash wallets will be tied to embedded LND nodes. This is because remote interfaces don’t expose their seed phrases and we want it to be easy for users to restore their self-custody and Cashu funds.

Remote wallets can still sweep Cashu tokens.

Down the road we may tie Cashu wallets to Nostr keys. It will be another bit of data to back up but might not be so bad if you are already use that key.