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.
What kind of question is this? Games don't affect you unless you play all day,maybe around the clock, and since games are involved with gambling many turned addicts due to the higher time frame spent on gambling. Playing a mahjong game or chess game won't make you a very smart person either, maybe only in the game but that's it, you called slot games a brainless game and I can it the simplest game. Slots games are not puzzle or math solving kind of game, if you need something like that you should find them, but engaging in slots won't make anyone a dullard.