Sounds superfluous. Ecash wallets send via lightning when the user is not in the same mint already, and typically can detect from the lightning address if they are in the same mint to send as ecash instead.

Ideally, users should not have to figure out whether they should send a transaction as lightning, ecash, liquid, or any other payment rail. Lightning should be the interoperability layer that is front facing, and everything else just happens in the background without the user needing to even know what is going on.