I think a better question here would have been; what could you have bought with the moneys you lost gambling?
Yes, I agree with what you are saying that most gamblers will lose money in the long run. But on the other hand, one can ask that question about everything we spend money on.
What could you have bought with the money you have used on cigarettes, conserts, junk food, pc games, expensive clothes etc. I see gambling as something you "use" money on. Yes, you literally lose them but you buy entertainment.
I expect to lose my money when I deposit, but I also expect to have some fun.