Brainless means something stupid or foolish. That is enough to let you know that slots, dices and roulettes are not brainless (stupid or foolish) games.
You gotta take the meaning of the word in context of statement, I meant, "brainless" word here as in playing games that does not require using brain.
Not necessarily. Having played poker for many years and now occasionally switching to games that don't require thinking, such as slots, I see some sense in what you say, but not enough to establish a general rule. If you watch videos of people in Vegas clicking away at slot machines like there's no tomorrow, you'll probably get that impression, and it's probably true in some or many cases. But you can be intelligent and play slots from time to time; the two aren't incompatible.