Luck is helpful for your trades, since sometimes it might just save you from losing big, or even boost your profit. But, I never do depend on luck, I never hope for them to come. So, luck is one part in forex trading which helps boost our profit or minimal our losses, but you should never depend on it. You are right, trading with only luck is not trading it is gambling, it can bring small profit but brings huge losses too, so we need to get proper knowledge and experience. Without having good amount of knowledge and experience, luck will not work.