Good question! Aerobics, like any other exercise, has multiple advantages. 1. It keeps all/most of your muscles working and in a healthy condition. 2. Secondly, it keeps you healthy by working off whatever you take in. It burns off all the excess calories that you might have taken in during the course of the day. 3. Most importantly, as you have mentioned, because of the intensity of the aerobics, it gives enough exercise to your heart. It increases the heart rate and the contractility of your heart because you need more blood to b pumped by your heart to the over working muscles in your arms and legs. When you do this consistently and over a long period of your time (months to years), like in athletes, your heart becomes more efficient in working (contracting). In Summary, aerobic exercises keeps your muscles fit, keeps you in good shape, helps you lose weight, and keeps your heart healthy.