Many years ago I worked at a company that had Ladbrokes in the UK as a customer. On my first visit to London, I noticed their storefronts and found them appalling. They were some of the sorriest, shabbiest public spaces I'd seen, clearly designed to extract resources from the least well off.
I don't really buy any of the arguments in favor of widespread legalization (and I include state lotteries in this). I could be ok with legalization for a few big events like the NCAA tournament because clearly there is some demand that must be met, but we should not be enabling gambling as a widespread daily habit.
Of course there will always be black market gambling and the state cannot protect its citizens from every evil, but nor should it actively enable them.