There seems to be something very Japanese about this to me. I get that there is a humorous component, but there's also something precious about putting so much time and focus into doing something obsessively well. This point is made more apparent in this case by the choice of pencil sharpening -- a practice that is easy to see as less important than many other things he could be doing. But that's kind of the point. It helps to bring the focus away from the utility of the practice, and point it more towards the idea of doing something well, regardless of what that thing is.