ELI5 Why is makeup considered a self expression

I have a lot of female friends who claim thay makeup helps them to express themselves. Even more, the process of applying makeup itself is like an art or creativity.

Actual example: instead of buying a lipstick of the colour she wanted her lips to be, a friend bought "wrong" colour lip pencil and lipstick. She now takes 30 minutes to do her lips alone because she shades the lips with pencil in grid pattern, then applies lipstick on top.in the end result the grid is not visible, and the the lips are a shade darker. When I asked why she wouldn't just buy one shade darker lipstick, she explained she was being creative and it's a kind of self expression.

Sounds like a waste of time if you ask me considering the result is the same.

FYI I am also a female and do use cosmetics. However I fail to see the romantics of this, I do makeup to enhance certain features, but I don't find it more creative than putting on nylon tights.

ELI5 why some women consider the process of doing makeup creative and helping for self expression?