Betting houses are businesses and, of course, want to make money. But when a customer becomes addicted, they eventually stop betting because they no longer have money to spend. In other words, they stop being profitable for the house. Furthermore, no business wants to be known as a place full of addicts; this damages its reputation and, ultimately, drives away other customers. That's my opinion.
For those addicted to gambling, I don't think it's easy to stop. Even if they run out of money, they'll likely borrow money from friends or relatives. Worse, they could engage in excessive behavior that could harm others, as addicts tend to be willing to take high-risk actions.
These addicts can be considered a long-term advantage for casinos, while those who gamble with good self-control won't be.