The world has a few anti-celebrities, and Kristen Stewart is definitely one of them. She is so anti-celebrity, it's a wonder she even showed up to be photographed for the cover of Elle.
This is a wonderful photo and a wonderful cover; however, Kristen Stewart never looks like this. She prefers a more dressed down look, and that's what people tend to see in her.
Now, both photos could be representative of her style and her choice of presentation. Going to Coachella requires a certain form of dressing down, so this isn't exactly a fair comparison, but I don't think you'll see Stewart in her Baltimore Orioles hat on the cover of Vogue.