I thought cashu would be good for sites like stacker news, exchange platforms and maybe bitcoin mixers, but I think it's actually bigger than that. Mints being able to prove that their reserves match or exceed liabilities is kind of a game changer for a universal, completely private, yet federated, interchangeable, unlinkable mintbuck denominated in sats with constant solvency proofs and automated bank runs to ensure as little damage as possible from any bad actors.