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?
From my experience, I'd say yes, slots, dice, and other games that don't require strategy can sometimes be boring, as if there's nothing interesting. That's why I rarely visit slot machines anymore, because I've gotten bored and have chosen to gamble on poker or sports betting, which keep me entertained and always offer something new to do.
But it all really comes down to the individual gambler, as each gambler has a different mindset.
On the contrary, these sort of games can be really fun for some gamblers, especially beginners who just started gambling and have little to no experience on gambling, hopping on the slot machine can be really exciting if you ask me. Because if you introduce a newbie to skill based games, it'll be even more boring for them because they have absolutely no idea of what they're doing and they'll lose more, and what's the fun in playing when you're losing all the time simply because you don't know what you're doing.