Another useful reason may be that if you sit on the left, as we do, then you will possibly yaw the plane to the right, to give yourself even more visibility. For example if I sideslip it's by yawing right, so I can still see. As a result the nose may disrupt airflow over the right wing. So put the pitot on the left.
However I don't think the nose sticks out far enough for it to be an issue.
It's probably, a tradition, or old charter or something.