But the actual 3D Rubik's Cube is also a really poor representation, because at all times you can only see at most half of the cube. I guess the point of making a 2D representation is to correct that problem. I can much more easily superimpose the missing connections you have mentioned in my mind's eye onto this 2D representation than I can remember the 3D layout of the half of the cube I can't see. Not everyone's brain works that way, but mine does.