This very much depends on the player and many of the common data points analyzed when looking at a golf swing. Club speed, launch angle, ball speed, and many others can be considered the target focus to help assess what type of shaft should be included.
The game has seen a steady increase in graphics golf clubs and for good reason. The stiffness of the shafts originally played more to the game of varying seniors. After many years of recent innovation, graphite shafts have been far more popular on varying professional tours. The flexibility of the shaft has helped many beginner golfers along with mid to high-handicappers due to a greater range of club speed.