It makes a lot of sense, it's easy to process nutrients out, a lot of the "good stuff" is fragile, but it's also easy and cheap to add in fats and simple carbs. Mac and Cheese and a can of tuna can be a family meal, but other than the protien from the tuna, there's really no nutrition in that meal. But it's cheap and filling, so if you have no money, you'll pick that meal to feed your family over something more healthy like chicken breasts and broccoli.