Sportsbooks and playing operations say they're a significant source of tax revenue for states, which is why states greenlight them in the first place. That's true, though simply how much cash is being raised can actually vary from state to state. According to the National Council on Problem Gambling, 2 million Americans have a extreme gambling problem, and another 4 million to 6 million a light or reasonable problem. "It's this additive effect of extra types of gambling which might be legalized and more methods in which you may find a way to gamble."