As the ancients said, people are as they say, and words are as they say. The meaning of writing goes far beyond literacy itself. Word is a "facade". If you are good at it, you will benefit for life. The handwriting is standard, neat and clear, which makes people happy to accept it. If the handwriting is messy, or even words are made at will, readers will lose its practical value if they interpret the "heavenly book" and can't recognize it.
Beautiful calligraphy, whether in study, work or life, will leave a good impression and enhance self-confidence.