Looking down from Fukuoka Tower I see this, and it looks very much like a church. Given than only one percent of the Japanese are Christians, it is certainly quite an exclusive location. Nevertheless, I think there is an answer. Few Japanese may be Christian, but you can see chapels with an attached ball room both here and there, for instance on better hotels. To wit, it is quite popular to marry according to the Christian rite in Japan. (To marry in Shinto is reportedly a complex affair.)