Words like aerobic fitness communicate ideas and ideas direct action that in turn influence results.
Using the term cardiopulmonary instead of cardiovascular helps define aerobic fitness and design tests and workout plans that help you reach your goal of having a strong and efficient heart, clean and pliable vascular system that includes your lymph system as well as strong lungs the the muscle that control the operation of the lungs.
Aerobic fitness is usually confused with one of its elements which is endurance. The assumption is that a runner is aerobically fit. Is a runner with clogged arteries considered aerobically fit?
The answer is no if you include the health of the vascular system that includes arteries in your definition of the term aerobic fitness.
How about a wrestler who gets winded because in his training, he has not learned to use his diaphragm breathing and instead he is doing chest breathing? Is he aerobically fit?
Again the answer is no if you consider the strength and the role the breathing muscles play in aerobic fitness.
The expanded definition becomes even more important as we age. Workout programs for those over 40 and fitness over 50 must consider the expanded definition of aerobic fitness that includes at the very least, the heart, the lungs, the vascular system and the muscles controlling the breathing.