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.
They are not brainless game there are just game that requires no skill just as some users here have mentioned already, beside it won’t affect your brain any way , because is not only gambling you will be doing all your life you have other activities, like going to work , spending time with your love ones stuff like that . So betting on casino games won’t make you dull is just for a short while you being dull is on you may be you stop doing some other activities that usually help to boost one brain power and stuff .