The air intake is controllable within the unit whereas an open fireplace generally has airflow from the home coming in from the front, fueling the fire. Air also comes from the flue and the ventilation from the flue allows the smoke to escape instead of into the home, providing the flue is kept clean.
Wood stove works to control the air brought into the unit. Airflow is still very much important as a complete lack of air would not feed the fire and simply dampen the flames. With each stove, you will find ventilation holes and an air control valve. The valve can be opened completely to allow for maximum airflow for the hottest flame and closed for less heating and a cooler flame.
