I hope gambling is for short term earning they won't provide any returns with your investment, even it won't have praise increase like bitcoin. Gambling is just a game you will make money when your guessing is correct other wise you will loose. No returns and No Guarantee.
It is not even qualified as way to earn even in short term. Nothing is certain in the outcome of gambling, therefore, it cannot be considered as way to earn a sure and steady income. Some gamblers still believe that gambling is like that, and that they are going to make money out of betting, and so they make it a daily habit and career to gamble each day, but in the end, they got nothing.
Making money in any way has an obvious risk, whether it's bigger or smaller but here it's all about luck.. you got a 50% chance of losing your money, so you should ALWAYS think before rolling the bet: are you ready for the loss? Do you want to risk it? Is it worth it, or you can go for less money?