Because CurX/CurY are indices into the array e.g. 0,1,2,3,4,5,6 and so on. If you use these as sprite positions they will overlap each other by one pixel. You scale it up by the size of the image you are creatting, in this case 16 x 16.
I would advise not using the constant 16 though, but definiing a Global constant OBJECT_HEIGHT OBJECT_WIDTH so you can easily change it. Generally you should not have constants that represent a value in code unless it is something like "200" for a score (say).