Any form of gambling can be profitable if you know when to quit or stop playing at the right time. If you can control yourself to not get greedy and withdraw the time when you have win some amounts then your losses in gambling will be minimal. I also know some people who makes money from dice sites and even sports-betting. But the main reason why they earn profit from it because they have the right discipline in gambling.
Yup you are right if you know when to stop your play and when to start to your game then you can make a profit in gambling. Especially in Dice game, if you know when to stop your play this game is more profitable than other skill games. Yes here we will win in long term but without having knowldge on when to stop we lose in the end of the game. If we know this then we can easily make money.