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.
My gut these days tells me its probably better for the humans in society if this stuff is left only to black markets because it seems like it destroys lives.