There is a cost involved to the merchant on every swipe which generally ranges up to 5%. Now, when the effective margin on fuel is less making the petrol pump owner pay for every swipe will make it a worthless proposition. So, the banks instead of charging to the customers, they charge it to the card owner.
however, there are cards likegiving you 5% cashback on all fuel spends.
Plus you can take advantage offor more benefits