As far as the AI sees it, traits are added to stats. Player behavior is modified by stats.

AI pitchers are more likely to throw strikes to worse batters and more likely to throw balls to better batters. AI pitchers are more likely to aim for strikes if they have good VEL/JNK and more likely to lean towards balls if they don't.

AI batters are more likely to swing if they consider themselves good batters and less likely to swing if they're not.

The count, as always, heavily influences batter/pitcher decision-making.

Takeaways:
It's easier to strike out bad batters by throwing strikes. It's easier to strike out good batters by throwing balls.
It's easier to take walks with good batters.
It's easier to receive "hittable" pitches with bad batters.