[hundove]

Hello all,
I've noticed that many put many shades of eyeshadow on top of each other, putting one color and then putting another color on otp, or sometimes even a third color. And many put so many eyeshadow colors in one look, sometimes more than 6 colors.
Is tihs necessary? If yes, why? and what does this do?
And when putting alot of colors on top of each other, doesn't it cover the shade below it that it wont even show? Isn't that just wasting that color since it will be covered anyway? sorry if I sound so dumb,lol....I'm still an amateur
Thanks for any explanations.