Then you'd end up paying LN fees anyway, why not just use LN itself?

Though

Hmm, yes, the implementation can be tricky. Ideally, the mint should be online all the time since it has a Lightning (LN) node behind it, or the LN backend should be running elsewhere. What is your approach for this?

Also, imagine you are receiving SATs through Nostr via nutzaps, not zaps (which would involve Lightning). When you receive these nutzaps, you have to mint them to your mint (since it is not publicly accessible). When you want to pay with them, you will also have to swap them to an online mint. Otherwise, the receiver most probably will not be able to redeem or melt them, as your mint on the phone has to be online and reachable.

At the end, it feels like the goal of running the mint on the phone works more like an accountability system. For that purpose, creating a simple wallet would be simpler.

Happy to hear your thoughts, my assumptions might be wrong if you have ideas to deal with these stuff