This is generally a way to write big characters with student announcements. After the paper is wrinkled, write in big letters. Because some places are not stained with ink, there will be an artificial vigorous effect. After mounting, the paper is still flat. Therefore, the purpose of this practice is to show the vitality of calligraphy works and the artistic conception of Gu Zhuo.
But this is just a form. If you want calligraphy works to have more artistic connotation, practicing calligraphy well is fundamental.