Sometimes it is real. Sometimes the difference in cost is more than the discount. Sometimes you are forced to use Pilot/FJ because other stations seem like they were designed for golf carts and don't have room for a bigger vehicle.
One of our favorite places to camp requires a route that only has two places to buy fuel that have even reasonable access, and even the Pilot on this route is the worst laid-out I've ever seen. Others require a left turn on a heavily travelled 4-lane road with no light when leaving or are inaccessible with an RV. I use Gas Buddy to plan the fuel stop and pick which one will be cheapest including the discount. A Love's is under construction along the route, so my planning may change in the future.
The free shipping on CW purchases is a new perk on the GS club membership that might tip it to be a better deal. I'm almost two hours from the nearest CW and since we are relatively new RV owners it has been handy.