Why do those calligraphers stand and write with a brush?

Calligraphy and painting stand for two purposes, 1, with a large space for activities, so that arms and wrists can stretch freely when filling ink (coloring) flat paper, paperweights and pens. 2. The vision is wide, and the starting point and ending point are not blocked when writing, which is beneficial to the overall layout analysis of calligraphy and painting. 3, standing posture can make the whole body have room for activity, which can alleviate the numbness and fatigue of the waist and legs. I hope you are satisfied and have fun!