I believe that a human being needs to center him/her self. Physical activity does a great job on the body. Religion does a great job on the soul. But these thing are missing something. I believe yoga and meditation can be a great skill to learn, and it fills a hole in our daily existance.
Should it be allowed? Yes. Should it be mandatory? No. Is it worthwhile? Depends. Not to me. Healthy? Probably. It's not unhealthy. But since there was no option with this criteria in your poll, I did not vote. As for the religious aspect, that's absurd. When I go to the gym and watch the yoga chicks in their yoga pants, there's nothing religious about it.