Do protein bars work?

Hey! Simple question, do protein bars fulfill their claims of having.. say, 10g protein? Obviously it depends on the bar but is there any fundamental issue with them regarding the making process or any kind of processing? I need to get my protein intake up as a vegetarian, I don't even eat poultry, just dairy. My parents are against whey protein since.. well.. social media propaganda. I do not wish to defy them. So, do protein bars work? They basically contain whey protein as far as I'm aware, and my parents don't mind me eating protein bars.