I have seen both, as well. More than anything I am inclined to believe it is 1) personal preference; and 2) necessitated by a physical need.

I am the opposite in that my SUB started out life as a flat bar MTB. For commuting and such the twist my forearms/wrists needed, even with bar ends left my wrists achy and sore, plus I could not move the controls inward enough so the angle of shoulder to wrist was too much for my neck.

I am happily riding that bike with 40cm drop bars with the tops just slightly higher than the nose of my saddle. This is a good, comfortable position for me. No wrist pain/discomfort, no shoulder/neck issue.