I know that is always a topic for Italy.
The new Italian Government decided (in fact) to remove the "block" of cash payment. Until now any seller (shop, guide, restaurant) cannot refuse a payment by credit card. Any kind of payment.
The new decision is that this is not anymore valid for any payment below 60€. So, if you are purchasing something costs 50€ and you have only the credi card, the seller is not obligated to accept it. You have to go to an ATM and have the cash to pay.
I am of the same previous opinion: who refuse credit card do it mainly to evade taxes.
(I have written "in fact" because technically they haven't deleted the law who say that is mandatory accept credit card. They have decided that a seller is not fined if he refuses the payment if is lower than 60€. Is like to say that you have to respect speed limits, but you are not fined if you are over the limit. Mafia thanks)