Money runs gambling. It gets transferred from a point to another. From the poor to the wealthy, from the wealthy to the poor.
Let's first talk about how the poor gives the money to the wealthy.... They allocate a huge part of their money (which isn't a lot in the first place) to gambling thinking that this would be the quick fix to their problems. This is how they give the money to the wealthy in this case the casino owners.
But the money can also go from the wealthy to the poor. If the tax from casinos gets collected by the government and is used effectively, it can help a lot of those in need. The money can be used to improve infrastructure, education, healthcare and etc.
That's what's happening in countries like Finland. At least for now. All the profits government gets from gambling taxes goes back to people.
Once they even had the monopoly over the gambling by having only government owned company that all gambling went trough, and it wasn't for profit company. All the profits that went over the jackpot price cap also went back to public. They funded ton of charity organizations, especially organizations that were helping addicts, as well as housing and educating people who have hard time adapting into society.
Imho it is a good system, especially if the company is transparent and audited constantly.