How widely useable is a 'cash passport' in Sicily?
I suspect people would not know what that is.
Use a debit card at a bancomat, and pay in cash.
Many places are cash payment only.
You can use a credit card at hotels.
All merchants must accept cards. They cannot refuse the cards for payments above 30€. This is the law
There are businesses here in Sicily that operate cash only.
There is a national law and we know that not everyone sticks to it ;-)
Just reporting what happens here....