It seems pointless to me when a straight edge and ruler will do the same job but both can also be used for other purposes. I dont think its worth giving the thing shop space when its finished. All right for you factory unit guys, but when every woodworking thing I own has to fit into a 3 x 5 metre garage, alongside all the paint cans and the dust sheets and the tile adhesives and the, and the, ....multi purpose is the name of the game and I dont have the space to store something that dedicated.
Scrap wood, is just offcut wood that is waiting to be used again. Once its too small to be used again, then its firewood and my neighbours get it delivered for free. 8)