I think it may have many applications. I recently received a package from a design firm I frequently use (they do cover designs, direct response, etc.). Inside was a beautiful four color book-- 100 pages with a soft cover. It highlighted their many designs and photographs over the years. It was done through on-demand printing. So while I see authors taking advantage of such technology, I can also see on-demand for specialized advertising. Interesting stuff.
As someone who has been in the direct response industry for 27 years, I find that you have an amazing talent for cutting through the clutter and getting to the heart of the matter. Much appreciated!