It’s all about preying on people’s insecurities and marketing to them in order to make as much money as possible. Once you look at the ingredients on those bars, be they Luna brand or any others, you realize that’s not… food.
Same with fat-free products which are often loaded with sugar and sweeteners and additives that try to mimic the thick consistency of full-fat ones and fail miserably.
Put plainly and bluntly, processed food is garbage. Apple slices dipped into nut butter are far more satisfying that a dry rectangle of crap. And cheaper, too.