I suppose it's good for qigong if someone wants to market qigong along with yoga. Qigong is probably more suited for aging populations who have some issues with asanas. As far as combining qigong and yoga, there is already tai chi and taoist yoga that incorporates qigong and gentle movements, stretching, and opening of joints and energy centers so this idea is not new, just new marketing.

I have tried QiYoga in London with Fiona and it is AMAZING. It is not for old people, it is very energising and you can feel the prana (life force energy) being harnessed between the palms and in the breath. It is such a well blended form of yoga and worth trying. It leaves you feeling empowered on all levels: physically, emotionally and spiritually

The combination of Qigong and yoga is definitely NOT only for old people. The two are acturally very complimentary and leave the practitioner feeling very alive and aware of their internal energy vibrating much stronger. Of course that sensation is acheivable with pranayama exercises as well.
Thank goodness peolpe are bridging the cultural barriers and bringing the universal healing arts togther into "new marketings" so that we can all be introduced to these wonderful prcatices.