They isolated the area of China from outside places preventing things like invasion and impeded cultural diffusion and trade to a degree. Its one of the reason China holds a xenophobic attitude because it was created in relative isolation and its natural forms allowed it to be isolated so it helped to reject outside culture.
once your an expert at mountain warfear........... you will know. for instance, back in the day, people falling to there death was a regular acerance. and fighting was worse. you had dragons watching the fighters fall off on a daily basis.
