Just got my new card, replacing the old gas-only card. What you want to do is put the Shell app on your phone and have your credit card (if that's what you want) listed as method of payment. So when you are at a Shell station use the phone app to pay for gas.
Or you can just pre-pay for your gas at the counter - I would NEVER put any card into the gas pump slot.
Or you can just pre-pay for your gas at the counter - I would NEVER put any card into the gas pump slot.