This might be the only solution they have seen to maintain or to keep their players inside their country, and also to gather more players. This is a good news for gamblers since they don't have to worry about taxation everytime they play. Japan really made a good solution to have more or for the fast growth of their economic situation.
This has been the wishes of every gambling sites which are heavily taxed by the government, they want to spend the money that the government is collecting to market their gambling site because the competition in online gambling is very competitive.