It's a totally personal choice. As long as you're staying under a calorie restriction, you'll lose weight. But bars in general just have a lot of 'gunk' in them. A lot of sodium, preservatives and such. But honestly they're still a better choice than most of the other bars out there because they have a better general nutritional profile. So if you don't mind spending the bucks, realize that it's not 100% 'clean' food, and have it planned into your calorie intake, there's no reason not to. Convenience definitely has its place.