Let's try to understand, why. First of all let's assume what we will understand as anti-system for our system. Every action is changing of specific parameters of an object of the action. Thus when we join together action and antiaction we receive the additional action, which is connected with stabilization of this specific parameter.
Functional block is very controllable.
It enables us easily to divide the contrary demands in time, space and relations and to resolve sometimes very hard problems. For example, let's take the electrolytic gold coating process. We want to receive the gold coating only on the specific surfaces. The using of the contact masks takes a lot of time to put an then remove them. You can easily resolve this problem now.