The main benefit of properly fit clubs is they CAN help you make a better golf swing. Of course they are not magic wands, as some advertisers would have you believe, but they can help you to avoid certain swing flaws. Let’s take “shaft flex” as an example. Golfers using shafts too stiff for their swing speeds often suffer from two common swing flaws: “casting” (releasing too early) and “hang back” (little to no weight transfer on downswing). They do these to try to help the golf ball get airborne. Or say a lie-angle too upright can cause the golf ball to go left, from where the player starts to aim or swing to the right; too flat-just opposite.
These are just two examples of many. That said, remember that fitting is only one element in improvement. You will still need to keep working on your swing-especially if you have fallen into one of the traps above. Our golf subconscious is brilliant and quickly finds ways to adapt to the old ill-fitted sticks.