It is in the form of a council [rather than a functional ministry] because its role is to coordinate. The heads of the relevant ministries are members of the MAC, and major policies must be harmonized within the MAC before they can be finalized.
之所以是委員會的形式，就是要發揮協調的功能，相關部會首長是我們的委員，任何重大政策要在陸委會溝通協調之後才能決定。