Not random use to pretty-up the information.
The teaching system uses each color to represent a specific concept. It also relies on relationship between colors.
Many other discoveries followed, such as insights into the grammar of financial language, and better ways to explain concepts. Today we say Color Accounting is as much about language as color. We obsess about words.
Two little words have a bad rap and often confuse people: debit and credit. We coded them green and yellow twenty years ago, but we are still finding fun new ways to explain them. Like frogs & flies.