It is close to impossible especially for players with small capital to gamble in order to complete the quest. Afaik you need to wager a lot of money in order to win the quest, so if the main purpose is just to go to Macau then it is better if you spend the money you have to pay for direct transportation and accomodation instead of spending it on such promotion on a gambling site. If you can take the risk of spending money, the promo can be something beneficial in case you win big while playing + the additional prize but on the opposite side, you may lose all your money and you win nothing from the promotion.