You also need to consider the potential for being away from help. No matter where you are in a lake, unless its one of the Great Lakes, you can get to shore pretty quickly in an emergency, and you can't find yourself unable to reach shore because of a strong wind or current to seaward. In open waters that is not the case, and in many areas, like the New Jersey shore, most of the inlets become dangerous or impassable when bad conditions arise.