@yjsmziwei9360,
The theory that I heard about the show's popularity in China is based on the notion that the Chinese love watching as proof that even the United States is flawed. The show is proof that there is corruption even in the government of the United States.
Personally, I have not seen a single episode of the show yet but I can't imagine why you couldn't study the show and mine it as a source for formal (proper English dialogue) language and casual (conversational dialogue) language. It's up to the listener to determine which one is which.