Cashu is custodial. The mint has the keys, the mint owns the bitcoin. It is a bank and has custodial risk.

However, cashu offers seamless perfect privacy. The mint knows nothing about who has their tokens, how many, or what anyone's balances are.

That privacy means that they can only ever rug everyone or no one. They can't selectively rug you alone.

Also in terms of receiver privacy, when you receive payments over lightning, you usually expose a node id. With cashu, that node id is used by you and potentially hundreds or thousands of other people. You're hidden behind an unknown and potentially massive anonymity set.