> AFAIK you could go to jail for having tourist money or USD if you did not have an official reason for having it (or it probably would get “confiscated” by police if they found it).

That's the theory, in practice see the article.

One thing to know is that owners of private houses with tourist guestrooms will make you huge portions so that their family can eat some yummy CUC food, even if they are leftovers, rather than the state rations. So it's absolutely not bad manners to finish everything!