I can see how it can be valuable for a lot of people, but honestly, I spent most of my life thinking about why I was so fat. The obvious reason being that I ate too much and didn't move enough, but why I did those things...well, I spent years thinking obsessively about that, and there is absolutely nothing special about my reasons; they're probably the basic laundry list. Thinking about it as long as I did may very well have helped, but I only started to really, seriously lose weight when I just decided to quit agonizing over it and get on with it. I spent too much time waiting for the great EUREKA! moment when I should've been changing my habits.
Obviously, mileage varies.