Performing core exercises is a whole lot more than doing crunches.
Crunches are great, but if you can strengthen your abdominal muscles while you are also doing other exercises, you increase your physical fitness level faster. An exercise such as the exercise demonstrated in the video above requires the use of many muscles.
Muscles being used includes the obliques (love handles), latissimus dorsi (back), biceps/triceps (upper arms), gluteus maximus (buns), adductors (inner thighs), quadriceps/hamstrings (thighs) and the flexors and extensors of the lower arms.
Exercises that help you work many muscles at the same time are rated as high value exercises. These types of exercises also help you improve your balance, flexibility and coordination in addition to increasing your functional strength.
As you grow older, functional strength can make a dramatic difference in your quality of life.