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.
It's pseudoscience but its method isn't scientifically based. I guess you're believing that it's science-based because of the calculation. But if you'll analyze the whole thing and also research what it means, you'll find that it's just all about superstitions. As being applied to lives and how to get luck, then it's also applicable to gambling and you'll see gamblers believing on it will say that they've been lucky because they've followed a certain suggestion from feng shui like putting some vase on the north side of the house, etc.