The lack of truckers is a big selling point also because while they're important to keeping the country's economy going, they also tend to be pigs who trash a place and lots of women get uncomfortable going into a place with too many of them around.
Pull the women in with clean bathrooms and an environment where she's comfortable and the kids follow. Kids pick up lots of candy, stuffed animals, t-shirts, etc. when they're inside. Not everyone cares about the local favorite dining experience when they're traveling, most just want a bathroom that isn't filthy with reasonably priced gas and some food they can grab & go. Buc-ee's gives them that.
Yup. I don't buy much at Buc-ee's, but love those clean ladies' rooms! One time we stopped at a Buc-ee's in July - families with kids were swarming the place - buying stuffed animals, candy, lots of food and drinks, etc. Smart marketing.