There are none, it is simply entertainment. If you approach it with this attitude, you may get lucky sometimes, if you go in hoping to come out wealthy, you will lose.
Anyone who goes into gambling hoping to benefit by being wealthy and not just for fun will not only loose all they have like you said but they will also end up loosing themselves at the long run. I personally do not see any way gambling benefits anyone.
Except for luck that makes some people win sometimes which does not shine in often, gambling is more like wasting of time and resources unless of course you just want to have fun which the last time I checked, there are so many awesome ways to have fun than that.