+1I believe attack is just how likely you are to hit; like low attack means a lot of misses (and/or dodges/blocks/parries never been sure if it's purely attack or defense, or a combination...), high attack means fewer misses.
(Either that or I'm misinterpreting either the question or stats in general (or both).)
Benefit is in the eye of the beholder, but I don't know of anyone who actively uses it...
Having a lower attack means the same thing as having a lower chance to attack
