I never was a fan of protein bars. A lot of them have detrimental stuff in it, sugar, and sometimes stuff you just don't want in your body, hiding behind the label 'protein bar' to be an easy sell. I'd definitely be critical if I were to have protein bars. I'm shelving my current protein shake because it has aspartame in it, and apparently traces of soy protein (which prohibits protein uptake) in favour of some brand called 'natural whey'. The way I see it, you'll grow tired of the taste of protein shakes after a while, anyway, and it's rather useless to have artificial sweetners in it, especially when aspartame has been linked to increased appetite (I think I can confirm this one, myself) and sucralose was originally a pestecide.
It's not really like that protein shake costs anything more, anyway. I just don't need articial colouring and sweetners in a health-product. I don't know what that stuff does to my body, but I know it won't make me healthier, so I just stay away from it. "Why not" is the way I feel about it.