Scott Bike Finish

I picked up my new Addict from the shop yesterday. Lovely bike, fast, light, agile, and based on my maiden run, everything I expected and more. Just one niggle. The first thing I noticed in the shop was that although the bike is matt black, the upper surface of the toptube is unpainted. The dealer explained that on their matt bikes, Scott spray paint the sides of the frame only, and while the upward and downward facing surfaces may get some overspray, they are essentially unpainted carbon, with these unpainted areas being irregular, and each bike different. Imagine somebody having taken some fine grained sandpaper along the top of the tube and you get the idea. The same is evident on the chainstays.  Although in daylight you have to look pretty close to see the effect, on balance I would have preferred a full paintjob! Does anybody have any idea why Scott do this?