Martingale is useful if you know how to use it on certain games but if it was a game that is purely dependent on luck then it is not the best type of strategy you have to use, to be honest. It will ruin you at the end of the day, mostly with lots of losses compared to winning. I wouldn't recommend this kind of strategy to someone if they don't have enough knowledge about the type of gambling they chose.
I have used a lot of strategy but most of the time I was failed to get a profit. I think no strategy will work since it solely based on luck. If someone gets lucky, they will win.
Yes, that is right. The strategy will only work if luck comes. But if you can combine the strategy with knowledge, I think the chance to win will bigger, and the strategy will work in the game based on strategy and luck. Perhaps, your win money will not be bigger, but at least, you can win some money.
Perhaps, when you want to use strategy, you should select the game that is not pure luck but it uses strategy to win so you can test your strategy and see if that will gives you a chance to win. That could make you use so many strategies because you need one working strategy to win the game and that is not easy to make the best strategy.