Just one example of tactical vectoring
In the Area Control environment if you have, say, two aircraft, one above the other approaching top of descent, the higher aircraft will generally require descent clearance before the lower aircraft. In order to provide this you can use tactical vectoring to turn the higher aircraft left or right to facilitate its descent, instead of being forced into a step descent situation. It all depends on your available airspace, of course. I understand in Mainland China you have to keep aircraft rigidly inside airways so tactical vectoring, as above, may not always be an option for you.
If you get the opportunity try and visit Hong Kong to see tactical vectoring. It is used by Area controllers and Approach controllers every day. Or if you can't visit Hong Kong try to get to somewhere that has radar coverage of the Hong Kong area to see it in action. Better, of course, to visit in person and have it explained to you.
On the beach