1) Some golfers think that custom made golf clubs must be expensive and hard to get done right. Their thinking is that most golfers are playing with standard clubs off the rack.
2) We are all individuals and golfers are coming in all kind of sizes and shapes. Why shall your club come off the assembly line if your swing did not come off the assembly line? Taller golfers need longer clubs. Golfer with slower swing speed and senior golfers need a light weight shaft with a softer tip section to get the ball easier airborne. Most average golfers need a driver with higher lofts than offered as ready made clubs in big box stores.
3) The advantage of custom built clubs is that they are custom fitted to your individual needs. You don't want to have your body adjust to the golf club. Custom made clubs aid especially average and high handicapped golfers who have the most to gain because game improvements can be immediately realized. The easiest way to lower your golf scores is to fit your clubs to your swing speed and physical body measurements.