Hopefully, we don't view exercise as just a means to burn calories. We should view calorie burning and fat loss as a by-product of exercise training (or any physical activity). The most important thing that we get out of training is the development of motor control and work capacity.
The hip is an important part of training and everyday life, yet many have such poor function. Walking, running, climbing stairs, jumping, and lifting anything requires good hip function (esp if you don't want to hurt yourself). The hips can be thought of the basis of all other movement (this is why we have our largest muscles here) and function to move our body against gravity. Knee pain and low back pain can sometimes be attributed to poor hip function.
The kettlebell swing is a great exercise to develop good hip function. It requires you to stabilize the spine, hinge at the hip joint and engage the glutes to extend the hips. As easy as it seems, many have problems (you may have had the opportunity to train with me and have had to been corrected in your technique many times).
Grant (age five) works on his kettlebell swings (with 15lbs, 30% of his body weight). He is getting better, but still allows his spine to flex and doesn't get full extension of his hips (probably needs a lighter kettlebell to do this). But, soon he will be able to do this easily (soon he will be bigger, faster, and stronger than me)!