Gambling is a hobby it something for a fun sake while trading is seriously for money making. I think there will be a very low ratio of people gambling and want to earn with gambling otherwise most of the people gamble to spend some quality time.
Only people who have lots of money will prefer to gamble as even if they loose it won't make much difference to them and they have enough money which can take care of their living but a person who seriously wants to earn some money will never prefer to waste his money in gambling as he is well aware how hard it takes to earn money and especially bitcoins so he will definitely choose trading over gambling to earn regular income.