They're not an economic boom. Casinos suck money from their local economies because they a) don't pay out on jobs or local purchases more than they bring in, and what they bring in from locals pulls revenue from other other local businesses.
At the end of the day, casinos don't bring much of anything into a community. Quite the opposite. Vegas only makes money on gambling and sees a net positive because it was ahead of the pack and has become a destination for outsiders to come in and drop money. They're a tourist city centered around gambling. Unless a city can replicate that, which no one really can, they're just asking for trouble with casinos.
Indian reservations and other locations can make money as secondary having destinations more convenient than Nevada for towns and cities around them, but none of them hold a candle to the money flowing into Vegas. If you legalize gambling and casinos in more states and dilute the pool of people going to places like Lake Charles, ShreveBo, or one of the reservations, you'll see they practically all just suck up money from their surroundings.