As the name says Convenience stores are designed and focused on providing convenience for their customers or consumers. Gas is a necessity when you are traveling out on the road with your vehicle, and stopping for fuel is part of that necessity because you have to fill it when it goes empty.
Convenience stores offer the traveler a one-stop shop for other items they might also want while traveling under one roof. To make the most efficient use of your time while filling up your tank, you can visit the store inside to stock up on snacks and supplies for the road.
It makes a big difference when you are short on time and need to maximize each stop you make while traveling. If you can stop, fuel up, get all the supplies you might need while also allowing the option of parking to stay overnight, that’s the option most likely chosen. Gas stations that only offer fuel are likely not the first choice for many long-distance travelers.