Every country has superstitions, urban legends, myths, and "magic." Some are well-known, and some aren't. Many people continue to believe in them and some try to preserve them, as a kind of national heritage of their country. Like the fairy tales, we tell to the children (or used to tell).
In any case, I believe that anything that makes you dysfunctional in any sense is not good. Wearing an "amulet" or having your socks be a different color because you believe that this way you will win is not a problem. Many times, however, the limits are crossed and your whole life revolves around these prejudices and superstitions alone and it becomes an illness. Anyone can think that it affects their betting in some way, but we all know that such a thing is simply not true.