I think its much better invest than to gamble, because investing is not so risky and you can earn good profit. But they are both risky, but on investing you need to wise. I think its better to invest because its safe and surely the money will not lose and expect good profit. To gamble is a game of luck whether you lose or win. I go gamble only when i have free time and its just fun an entertainment.
Investment is better if you are not a gambling enthusiast though investing itself is also a gamble and you have to know what you are doing and where you are investing. It's not that safe because there is also a risk in investing and you have to understand that not because you have invested, you'll guarantee return of investment and profit in due time. But it requires, dedication, patience, time and enough knowledge to grow it.