Yes, gambling is a business with a huge turnover, so to reach users, they must promote themselves. It's certainly expensive, but I think the rewards will outweigh the outlay. We can see large, well-known casinos today doing the same thing: massive promotions, but they're also effective.
Everything if is bad in strategies and executions will not work well and does not lead to good work efficiency including marketing programs. Business can run marketing but they have to consider many things, reference their past programs and results as well as marketing strategies of competitors in a same gambling industry before making and launching their programs.
It does not stop here and along the way, they must assess results from their marketing programs in order to make sure will they continue them or stop or any necessary changes for improvement and get better effects.