For the club to apply all of the energy we put into it into the golf ball it must swing freely through as if it were a pendulum.
Using the standard roll over fore arm actions this requires great timing, since the downward un-cocking of the wrists must be coordinated and timed with the rolling over actions of the forearms.
Due to this type of arm action only those who have been blessed with excellent hand eye coordination are able to learn it easily. These people could learn to juggle or do a similarly difficult skill quickly, where those who are not blessed with these skills from birth must labor long and hard to learn it if they ever learn it at all.