Maybe a way to appear appease certain nobility that couldn’t write for shit?
As someone who does calligraphy sometimes (I should practice more lol), those "chicken scratch" styles are very hard. Most people can't read them because they are not familiar and can't write like that themselves. For example cursive kanji is real hard, and yes, hard to read. But you certainly can't sloppily write kanji and have it turn out the same as cursive kanji. The nobility certainly could write very well, and legible if they want. That's the thing: they were nobility and had time and money to practice things such as calligraphy and poetry. These styles were not to appease nobility, the nobility themselves developed them. The peasants were poor and had to work, they couldn't even read, let alone write, and had certainly no time for calligraphy.