Great point.Advertising hyperbole aside, fear is a double edged sword..........it's usefulness depends on the situation, and a couple exact definitions of exactly what we mean by 'fear'.
Fear can be useful, both to spur us on when we're running from a bear or the like, and to warn us that we're about to do something rather unwise...
Being afraid doesn't mean that you don't act -- but at least, if you're afraid of something reasonable (not a phobia, etc.), your body and mind are more primed to deal with the dangers.