Couplet is a kind of running script, commonly known as cursive script, and all strokes are connected end to end.
Meaning:
1, when used as a derogatory term, describes the illegible handwriting.
All he writes is practicing calligraphy, and ghosts can't understand it.
As a compliment, you can say: His handwriting is great, which shows that his running script is good.
The advantage is that it not only accelerates the writing speed, but also forms a unique style of personal writing.