I don't know if this is just a "me" thing, but I get motion sickness from the rotation and swerving that occurs when your ship sails through a storm. I don't mind a bit of realism in my RPGs, but I'd prefer not to get seasick IRL when I go sailing ingame 
(There is also a minor glitch that happens if you swap maps while you're on a ship in a storm, your camera will continue spinning. So being able to turn off the spin might be useful for this beyond motion sickness)