A lot (most) of my work begins life as a simple blue col-erase pencil sketch. What I like to capture is the warmth and imperfection of a hand drawn line. Designers can refine and smooth until some level of perceived perfection is achieved.
It can lose something in this process however. I call mine ‘scribbles’ and don’t rate them particularly highly… but most of the tricky layout problems are worked out at this stage.