Yes of course. As with any "convenience food" like the little boxes of cereal, its meant to save you time. If a big box of Cheez-its says 100 calories per serving and the serving size is 20 chips; it saves you from getting the big box, getting a baggie, and counting out 20 chips. Of course if it saves you time, its more expensive.
7-11 items are more expensive than the regular store. At least at my house 7-11 is around the corner and in walking distance. The store is a mile or 2 down the road.