As time trudges along and more and more painters around the world are finding the beauty of the airbrush, I have started seeing more and more wargaming models that put the wonderful tool to good use. Some of the more pronounced of these examples make a serious use of the airbrush to go far beyond the simple base coating or even just a quick zenithal highlight. They task their brush with actual highlights, added armor detailing and weapon effects. I've seen many object source lighting examples done with an airbrush all around the web as well.
The question at hand lies in the aesthetics inherent with airbrushing the majority of a model. The finish feels softer in many cases. Transitions more subtle, but at the same time noticeable as being airbrushed depending on the space. There is a balancing act between brush and airbrush that many examples I've seen that are on the heavier end of either side. Some use their airbrush for very simple tasks. Others for as complex a task as they can possibly control. There are others still that try to strike that balance between the speed of an airbrush and the look of the brush. In the end, it's all up to the viewers, customers, or painters aesthetic choice. How you perceive and enjoy a look of the finished model is what is most important.