Gambling is also an investment, yes, the reasons people gamble is to make money, and no one wants to do something he won't benefit or make gains out of. There are some persons who do not go anywhere to look for work or do any other thing, the only thing they mainly do is to invest in gambling, and they make huge amount of money from it, so yes, we can also say gambling is a big time investments.
However, it is good to gamble wisely to avoid emotional hallucinations, trauma and other mental problems coming as a result of lose of funds through gambling, because one of the things that can render a man useless in life is gambling of investing heavily in it, if you aren't really careful, you will lose the amount that you weren't intending to lose and it will affect you in all ramifications.
I believe some people see gambling as an investment, especially if that’s their means of income, but for me I see differences between gambling and investment that they are completely not the same, because I see gambling as game of luck, not investment, when you bet, that mean your money is at risk, it either you win or lose, you are not really sure of it return. I believe a lot of people take it as investment because they make money from it, but it kind investment that what you lost is bigger than what your gain. While investment in other hand, is sure and legit, you can invest and have rest of mind, because your something most surely comes as a return.