some people will say superstition, but it all goes back to each individual about luck and fengshui itself, different in my country there are also those that are so like auspicious days, good dates and usually for weddings not for gambling
I don't think it's superstition because from what I've read, feng shui is the science of layout harmonizing with the owner. So by knowing about the person's matters and using the calculation of feng shui, it will get results expected to bring good to that person. But I don't know if it's applied to gambling because I don't know much about it and don't learn about fengshui. But some people call that related to superstition as things are not available in many countries and cultures.