I used to live in Korea and I'm very confused. It's a very very strange location. It's not close to a major metropolitan area. The (small international) airport's far away with no direct route to the circuit. There's not even decent hotels to stay around. It's considered by Koreans as a mildly interesting travel destination. Why did they pick this site again?
It's like having a race track in... Oregon and asking people to come and see.