Hi Diana,
SFQ exercise insures your internal health, healthy organs, helps you relax...important stuff! I don't think it replaces aerobic exercise. You can find related Chinese exercise or martial arts, etc., that are more outwardly physical. or, more western activities. Both are good. Qigong is better for longevity if you only have time for one. As you get older, the western forms of exercise should be toned down. Most westerners don't understand the concept of storing and saving energy,,,,just using it.I see older people running around the lakes here, that shouldn't be! They are battering themselves. Wearing out their joints..
Also, qigong can allow you a healthier base, and a longer ability to do the other types of exercise. Keep that tongue up, even when you are aerobisizing to Disco Fever. Qigong awareness will help you define other forms of physical movement, in a healthier way.