Investing in betting sites or betting our self?
yeah it is profitable and also your investment may return loss as well .
This is because if a player losses you will get profit and if a player wins your investment will return you loss.
There is no limit to you return whether profit/loss. Some of the sites provide margin/multiplier to control the profit or loss(bitvest.io)
Let me ask a Question from you, Is it profitable to invest your money in gambling site? I think its more simple and clear, Because everyone Knows that "Gambling is Play at your Own risk" Its equal chances that you may loose or Win. But result is always negative. Because when you won a game you tries to play another in which you loose your money. There are many example. Those who can not control their nerves while gambling they always loose.
First thing first - Are we talking about investing or gambling?
Second thing - It is not likely that a user who won a game will always play another game.I agree with your statement but it is only limited to users who doesn't have any self-control.However i will like to markup some things that all gamblers are not without self-control ,there are still many gamblers who are pretty smart and can switch over strategies time to time to reap up some profit.