Balance is probably the main reason, most helps are on the edge side so putting the kicker on the port helps keep things in balance, at least on my boat. Lots of folks create steering devices so they don't have to lean over the stern to steer. I have found that if my main engine has just the snag in the water, it will steer just fine when my little kicker is locked in straight forward. In fact, I had an electrical issue in my big motor and had to use my kicker to get back to the launch ramp. Stayed at the helm and just used the main motor to steer and played with what steered best at what angle. It was well over a 5 mile ride back to the launch, thru some narrow channels where steering was critical. Had no issue maneuvering all the way to the launch with just the skag of the main motor in the water to reduce the drag and keep my speed up..