Which entry point do you suggest looking into?

Ah right. Though “pay back" and "cash out" would be seen as the same thing I feel. The only path to argue that I can see is to argue that Cashu tokens represent a form of gift certificate. But gift certificates are supposed to be non-monetary, limited-purpose instruments. Depending on the country, customers can sometimes get a refund on higher-value gift certificates, often on condition that they ID themselves and jump through a lot of other mandated hoops. But for smaller gift certificates the merchant is not allowed to refund. And when it comes to giving change, usually the customer can't get back any change except if it's a small amount in view of the original value of the gift certificate. So they’ll just add a pair of socks or whatever to use up the remaining amount. What you’re suggesting might work if you *must* spend *all* your tokens at that merchant (once obtained there is no way back to the lightning network for your tokens drawn on their mint). But then besides some of the niftier programmatic aspects of Cashu you lose a lot of the value and it becomes something like a virtual in-game currency. Cashu could still be a good backend for only that though, which goes to show just how versatile it is.