I think they want to get their money out of china and parked into a safe place. If they pay off their mortgage, they don't want to find a new place to park their money, they can just keep the house as an asset. I think a lot of investing in china is real estate based and is part of the reason that market is struggling over there so much now. It would make sense for them to continue to follow that investing model when exporting their wealth to other countries.