That said, on the general topic hinted at by the title: Yes, they do.
I followed Gordon Ramsay's many videos for a couple of years. I went from being able to a repertoire of eggs, rice and barbecue to cooking as close to world-class meals as I can imagine. This, to the point that we stopped going to expensive restaurants because, in most cases, the food is inferior to what I am able to cook at home. When you come out of a restaurant with your family, having dropped the equivalent of a car payment for the meal and your kids tell you "Dad, what you cook is massively better than that", well, you know you learned something.
I also helped me learn and understand about such things as sauces, spices, proper preparation and generally giving me a sense of the things I can experiment with, have fun cooking and have more variety at my fingertips than just three dishes.
So, yeah, for me, absolutely. Of course, what you get out of it is a function of the time and effort you put into it.