So, having a unidirectional channel to a mint reduces the exposure to custodial risk without the complexities of running a lightning node. No need for liveliness vigilance and incremental backups. Its almost like sending a lightning payment where the first hop is custodial but adds more privacy through time decorellation and blinding. Or receiving a lightning payment where the last hop is custodial but always online s.t. zaps can be received while offline.