Yes. Your skin is a Vitamin D making machine. It is now pretty common knowledge that Vitamin D plays a very important role in your over all health and in the prevention of many serious diseases, including cancers.
Skin exposure to UVB is the only practical way to get Vitamin D naturally and in the quantities that our bodies have come to expect (and require) over the course of our evolution. Since a Sunbed provides up to 100% exposure of all your skin, it means that much less exposure time is needed to produce the same amount of Vitamin D than if you are wearing clothes and the light is coming from only one direction. Moderate, regular exposure to UVB is part of a healthy lifestyle that many of us choose.