She's honest about her life.
Much has been made of the Lena Dunham-is-rich-and-privileged narrative, and in her proposal she owns up to her roots and background. She describes her father as "a very severe WASPy painter whose images of men with dick-noses sell at auction for fair bit of money" on page 10 of the proposal. And on page 13 she says, "I had a lucky little girlhood."
It explains some of the things you've always wondered about.
Some criticisms of Girls have been about Dunham's character's sexual relationships. Why does she let guys treat her awfully? Is she a terrible role model? The real Dunham (not her character of Hannah) writes on page 14: "Being treated like shit is not an amusing game or a transgressive intellectual experiment. It's something you accept, condone, and learn to believe you deserve. It's so simple, but I tried so hard to make it more complicated." (The chapter on dieting also answers the question as to whether she has actually ever eaten while showering.)
Her pop-culture touchstones are familiar.
She mentions Holly Hunter in Broadcast News. Claire Danes in Little Women. Jane Eyre. She knows her audience, and they're likely to respond to the characters she brings up in her talk of "love," "sex," and the "big picture."
People will be able to discuss Dunham and race again.
In the proposal there's a section on Dunham's travels in Japan, in which she writes about the culture from an outsider's stereotyped point of view, at the same time admitting her ignorance (her travel chapter is titled "offending people in Sweden, Japan, Israel, and Cuba"). While frankness doesn't necessarily doesn't redeem Dunham, it certainly feeds the beast that's interested in her, and continues conversations that captured a lot of people's attention last year.
It's actually well written.
Dunham's a good writer, and she likes good writers (note the Didion quote early in her proposal). She knows how to construct an essay, and there's something to be said for that.
Update Monday, 5:33 p.m.: Gawker has removed the proposal after being contacted by Dunham's lawyer.