Flat bars are held at wider points, so you have better leverage over your steering. This lets you steer with less effort and greater control, so you can have more precise input. This is why I prefer them for commuting. I dart and weave around obstacles, and flat bars are more comfortable for this.

Drop bars are perfectly fine for most dodging. You'll just have to get used to the narrower hand positions and less efficient leverage. Once you do, the muscle memory will take over and you'll be just fine.

I just prefer flat bars because the maneuverability advantage is more important to me than the aerodynamic disadvantage. Of course, preferences change, and mine could change next month or next week.