It's said about brain that, "use it or lose it" — now, question being, do you think if person plays brainless gambling games such as slots, dice for major part of his/her daily routine, will it make him/her dull?
Edit: "brainless" as in playing gambling games that does not require using brain, I thought it was clear especially given examples.
If someone plays mindless games for a long time every day, then mental stimulation can gradually decrease. The games you mentioned usually require thinking and strategy. If this continues for a long time, the brain can become lazy, the interest in learning new things can decrease, and it can be difficult to maintain attention. If we want to keep the brain fresh, it is important to do some things like reading books, learning new things, talking to people around us, these things keep our mind and brain fresh. We should not do anything that makes our brain lazy, boring, less thoughtful and less interested. To keep the brain healthy, we need to do something that we can do with our minds and learn new things.