Custodial banking, but no user accounts. No liquidity management, no channels, all the privacy of using cash without registering with a big bank.

Your phone gets tokens from a cashu mint like you get cash from a bank ATM and you give bitcoin to others from app to app like you give cash from hand to hand, but also you can pay lightning invoices too (the mint handles it for you just like any custodial service) and the mint won't know whether the tokens you are giving them to pay your lightning invoice was the one they gave you, or the one they gave someone else.