Dunno. I am seeing mints as a routing service. I don’t ask the internet to route my packets, it just happens. I see the same thing for routing sats. As for UX, I see the user being not aware, nor caring what mints they use.
Discussion
Users will only care about sending sats between email address formats. Under the hood, it can resolved as lud16 or nip05 and the appropriate transfer is invoke - lightning for lud16 and Cashu for nip05. The user won’t care.
A routing service to where?
Their custodial LN balance?