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Perhaps, that person is very desperate on how to win in gambling games. They tried to believe in voodoo and try to use that "magic" to help them to win. . . . So perhaps, voodoo is still used by some people who really believe in that thing.
Yes, there may still be people who believes in voodoo while gambling. Apart from being desperate, as you have said, maybe they believe in such because they had the experience. I mean, they used voodoo before and then it worked well with their gambling, they won. That's why they continued that belief. Maybe a big setback is the only thing to change their minds. Or maybe it won't. Who knows, right?
In my honest opinion, nothing really works hundred percent of times in the world of gambling. People have developed such strategies over time just to find a way out of their frustration. I mean what can control luck. Nothing. Gambling is all about luck. If there were any tricks, then this world would have been full of rich gamblers. The only thing that gambling can bring is bitter experiences ultimately.