if "the experts" are telling you that there can be a winning strategy for dice, slots or roulette, just ignore them and move on because most likely they are just sick addicted gamblers looking for attention.
Well, on the contrary I would say that the place of experts cannot be completely ruled out. You may see that experts are only mentors but that role of mentorship is what has motivated many to winning. It is very possible they lie about their achievement but this lie keeps the mentee on the game with high hopes of winning and it really works. Gambling might be a game of luck but there can actually be strategies that make winners.
Researching for the statistics of the player could really help you win the game. We must base first at their winning percentage, if it's high we can rely on that player.
But, no gambler is ready to find time for such researches. They are all in rush to test their luck factor and keep trying on that. I guess if a gambler finds time to derive some strategy which could be anything like a mathematical based or based on skill and experiences of other gambler, whatever it could be, but definitely it may help them to increase the chances of sustaining even not able to hit the bull's eye.