Take the advice, leave the attitude.
Courtney's book is a conundrum in that, despite its age, it is still useful and relevant for libraries to have. Many of the products she recommends are classics that can still be purchased today, and unlike most books from 2007, the majority of the URLs still exist and work (!). On top of that, the advice is quite sound, so that someone who didn't have, say, a beauty-savvy parent, older sibling, or other friend/relative to shepherd them through this topic would definitely benefit.
The problem for many collection developers will lie in the tone. Courtney has some notions about gender roles and stereotypes that played well in 2007, but sound like cats on a piano in 2016. Much of her humor is at the expense of other kinds of women (feminists, "crunchy granola" types, etc.). The effect of this is really uncomfortable, because you'll be reading along, having a good time, and then Courtney will make a snarky remark at the expense of other women, and you'll feel terrible. It almost goes without saying that all female readers are assumed to be straight, though, to be fair, her advice is definitely inclusive of women with darker skin tones.
Library-wise, this will play well in smaller communities and collections in mostly white, middle-class areas. Larger collections should weed this and replace with books with more neutral language and/or more inclusive definitions of womanhood/femininity. It's a damn shame, but, this is why we weed: the world moves on.