There’s an interesting phenomenon when it comes to people in general, and casino players in particular – most of them don’t believe in numerology per se, but their answer would still be “yes” if someone asked them if they had a lucky number.
Numbers might be easily used to spot patterns and structure. But generally your conclusions will not mean anything, unless you know math very well and only ever use numbers scientifically, for example to invent and improve technologies. Despite that, people believe that there are numbers that can influence reality more than others.
Some examples of using belief and superstition in gambling might be considering the number 7 to be bad luck in craps, or choosing ages and birth dates (either yours or your loved ones’) when playing the lottery.
In the end the only answer to the question of lucky numbers is the fact that the outcomes of luck-based games cannot be controlled or influenced by the player in any way. So in order to create a sense of control over luck, gamblers will often choose gullibility over uncertainty. That’s where sticking to lucky numbers comes from, no matter how little sense it makes in reality.