Partly financed by Malaysia's favorite son, George Soros. Saw that Cathay's first Chek Lap Kok (Hong Kong). What exactly they intend doing with them is a bit of a mystery.
Hainan itself is in the throes of a massive development, adding beach resorts, hotels, casinos and the like. Remember though, that it's principally aimed at Chinese tourists, so it may not be exactly as you imagined...