The first benefit of yoga is that it can be done with just about any illness/disability without a problem. Even if injured or working with a disability, it is still important to stay active to stay healthy. Sometimes even the easiest movements can make a tremendous difference. Practicing breathing exercises to help with lung capacity, easy twists, all the way to moving fingers and toes is doing something toward well being. I've held numerous classes for children to adults with disabilities to help them find relief. There is always something to do.
The second benefit is that it teaches children much more than any physical activity they will do. I was suggested yoga to help with back pain from Scoliosis, but I ended up getting much more out of it than just pain relief. Teenagers have many emotions and it is far from easy. There is stress from kids at school, changes physically and all while establishing their identity. Yoga teaches kids how to channel their emotions in a positive way. Yoga teaches kids about their mind and body, without even trying. This awareness is what starts the ball rolling. It's not what emotions are present, it's what is done with them. Yoga teaches kids how to manage that.
The third benefit is teaching kids how to breathe for optimal health. As I just mentioned yoga brings awareness. Breathing is something that we do without effort and we aren't consciously aware that how we breathe effects our health. Breath is our life force, yet we often take it for granted because it's not something we have to work for. What if you were told that if you took 10 deep breaths every day it would improve your quality of life; younger looking skin, weight loss, less stress, etc. We do and buy many things because of the claim it will improve our quality of life, but the one thing that is free and completely in our control we often do nothing with. Yoga teaches kids how to use their breath to expand their lung capacity, so they can swim farther, be healthier and manage emotions.
There is always a time and place for yoga; 10 minutes, one hour, in a hospital bed, living room, class setting... There is no right or wrong, there's only the first step. The benefits are too great to ignore any longer. Don't take my word for it, give it a try!