It is important to train with sticks too thick to grip optimally, as well as those heavier than you would use in competition or for defense. You never know when you might have to pick up something unwieldy.
It is also important to hit the post with heavy and reactive weapons. A reactive clublike a hollow bat—will want to bounce a lot and you have to be able to break that and use that. With a heavy stick on a post, you are practicing keeping the stroke on course to get to your next power point after it bounces back.
This is excellent practice for machete fighting and swordsmanship as it makes you concentrate on edge-on striking and improves grip stability.
James LaFond demonstrates techniques for training heavy extension weapons, such as canes and bats.
link jameslafond.blogspot.com