My Little Pony: Friendship is Magic - Image #231,812

… yesssss ty god…. no.. not god… THANKS: GUTHIX, CELESTIA, MOLESTIA, JEBUS, SANTA CLAUS, LOL GUY, FFFFFFFUUUUUUUUUU guy, fuck da police, and DAT OLD NIGGA THANKS!!!

@Swichb1ade
I don't draw either, but the simple shapes are meant to help with visualization and alignment.
It's also far easier to make corrections early on, and it can help create consistency between multiple artists, like a cartoon animation staff.
There are some artists, though, who don't use circles at all and still make amazing stuff, so it's not mandatory at all.