Why did Mr Han (Sek Kin) enter of the Dragon give up Chow Gar Mantis?

Sek Kin once trained Chow Gar Mantis under Lau Soei, but he gave up after 6 months because the style did not suit his film work because it lacked fancy techniques so needed for the film industry at that time. Also Sek Kin said that the style was a very hard training, meaning a tough regime.