Lib she doesn't do it to sell records, she does it for the art. She controls every aspect of her songwriting and performance and she loves every bit of it. Do some research on her before you put her in a pigeon-hole.
It wouldn't suprise me if she did it for both. Not necessarily for money, but to get noticed. A large part of making it in the art world is just getting noticed. The music videos and the crazy outfits might also serve to propel her into the spotlight. There are other precedents: k.d. Lang, Elton John.
I think her current style is hugely influenced by her current position in the music world. Her artistic practice will probably change overtime, and could very well move away from where she is now.
@iamzack: Insulting people by calling them a retard doesn't further your goal of convincing people you're right. I agree with you on a lot of issues, but not the name calling.