One HN user wrote about why she liked them in a previous thread on Nasty Gal:
If you're like me and wear pretty much the same thing everyday bought from thrift stores (excepting underwear), it can really open your eyes. Women do, generally speaking, all look better than men. I probably spend too much on outerware, but I save on clothes because I just don't care.
As an anecdote, one of the baristas at my coffee shop said a ski pass at our closest resort (I'm in the Rockies) was too expensive while wearing, what I thought to be, fancy clothes. After 9 months of interaction, I've concluded her clothes budget would cover 3 ski passes. My parents taught me to value experiences over material goods, and I'm very thankful for that.