In Sicily I loved the automated payments - compared with the alternative. The petrol pumps were automated on one side and "assisted" on the other. Spivvy attendants spot the rental cars and wave them into the assisted side where the perol costs 25% more.
The other gotcha is when filling the tank prior to returning it at the airport. The car has to be returned with a full tank but the automated system demands that you prepay for the amount of petrol you need. You have to sort this out with the aforementioned spiv watching and smirking.