The "I embrace my hidden identity by exposing it without shame" trope is a lot more refreshing than the Hidden Identity superhero trope. Although I don't know if she is going to actually just live as supergirl and forgo the civilian identity, looks like she might.
Although the trailer is following the glasses and unstyled hair brand of "disguise".
I think the devil wears prada thing is just a point of contrast "Oooo, look at where supergirl started out,a lowly abused assistant, and look at where she is now".
Also, nit pick, Superman actors usually act restrained, like the world to them is made of toilet paper. But This actress doesn't, she acts totally normal as "the girl" and . She accidentally bumps into someone in a crowd, she should of at least separated a shoulder with her super strength.