This is a tough question that I have mixed opinions on. 

On the one hand, I very much value freedom and I don't think the government should get involved or have a say in how competent adults are spending their own hard earned money. What's more, talk of the legality of gambling induces fear of a potential slippery slope in which the government then gets involved in other aspects of our lives that it has no business interfering in.
As long as gambling doesn't result in bodily harm to the gambler or anyone around them, paternalism would appear very unjustified. 

That's one side of the argument that I'm convinced of exactly half of the time. 

The other half of the time, where I do think the government should get involved (perhaps not to completely illegalize gambling, but at least to set some limits or cool down periods between sessions or something) is when I come across a gambler. More specifically, when I come across very vulnerable people with clear gambling problems who are unable to acknowledge that they have a problem or unable to find help or support. These are people who have no money to buy their children Christmas presents because they gambled away their last $20. These are people who destroy their relationships with their family members and close friends because at one point they "borrowed" money intended for something else, but ended up gambling it away. These are people who turned to gambling because they already had some other mental health issues or trauma or loss happen in their lives that led them to be unable to find excitement or pleasure in anything besides gambling.  These are people that perhaps the government should be taking care of, because they may not be capable of taking care of themselves. Maybe this is an instance where paternalism is justified, similarly to paternalism with regard to hard drugs. 

So what am I really proposing here? 

I'm not quite sure. All I know is that, to me, it seems wrong for casinos (whether private or government-run) to be taking advantage of these vulnerable people. On the other hand, it seems wrong to deny them freedom from the one thing that brings them hope or excitement or pleasure.

Maybe what I want to propose here is something like not allowing players to gamble more than a certain percentage of their annual income. Or, perhaps as a less strict option, requiring all members entering a casino for the first time to sign a form indicating how much they're willing to spend per week/month/year, or how much they're willing to lose. Maybe this can be a specific amount or a percentage of their income. This would then stand and the player would not be able to override it without a long process that would require a lengthy cool down period, during which they can change their minds. 

Again, I'm uncertain of what I want here. I want freedom to be maintained, but I also don't want to see vulnerable individuals being taken advantage of by a system that creates problems but doesn't make enough of an effort to address or fix them, and I especially don't want to see innocent people, like the children of gambling addicts, getting hurt.