When you constantly use a particular service station and do not travel out of that area using the credit card that they issue is perhaps a wise decision. You are able to keep up with your fuel consumption, maintain the same quality of fuel and oil in your vehicle, while earning free fuel. Many people like having this type of service in their own neighborhood. Even though you get the "Gas Credit Card" from your local service station many times they are affiliated with major oil companies who maintain a service with major credit card companies so this will enable you to use your credit card at other gas stations.
Your local service station provides you with a "Gas Card" that you can use with their particular brands; however, much like the airlines the credit card rewards program is not usable with other fuel companies. When you do use the card at another service station you do not earn your reward points. Many times since the credit card carries one of the major logos like MasterCard, Visa or Discovery it probably is good at other stations to purchase on credit but will not be effective towards earning reward points. In some cases the "Gas Card" from your own local station is only good at that station and you cannot use it any place else for credit purposes. You do need to make sure that the card can be used at more than just your local station for credit in order to get the most out of your card.