BP Gasoline and "Invigorate"?

More and more there are petroleum companies producing what they distinguish their gas as and engine cleaner. BP - Shell and many others are advertising this. Ok great! Let say if you have a brand new car and from the start you use BP with invigorate all the time. Why do we need to clean our engine of deposits if we used what was suppose to keep our engines deposit free from the very beginning? Their ads have alot of loop holes in their claims. Or not?