Do you think Production Planning is important in your company? why?

Without planning one can not. achieve any exact goal.

It gives trends for demand and future expectations

How to effectively and efficiently utilize resources and minimize cost 

Yes.production plan will allow my company to meet the following objectives:

•  Minimize costs / maximize profits

•  Maximize customer service

•  Minimize inventory investment

•  Minimize changes in production rates

•  Minimize changes in work-force levels

•  Maximize the utilization of plant and equipment