A cashback bonus is money which is refunded to the player once they do something that qualifies them in the betting house. This could be failing to win a risk-free bet or making a certain amount of deposit. The obvious benefit is the removal of the betting risk and elimination of unpleasant costs.
Macau is a Chinese autonomous region, much like Hong Kong; formally a part of China, but with ample political freedom. While Macau is often regarded as the gambling capital of Asia, online casinos are not regulated. However, as gambling is popular and legal, many international live online casinos accept players from Macau.