Many people said the gambling is just a game and another people said it is Investment. How do you think?

Wagering of money or something of value on the event with an uncertain outcome with the primary intent of winning money or material goods. Gambling are requires three elements such as consideration, chance and prize.
Very exact definition, so it does not mean that playing in casinos are only considered gambling because it was not specified in the definition, even trading itself is also a form of gambling because we want risk our money to get a better price which is the profit we will make.