mte. Her job is to write, record, and sing. Sia, for example, now performs with her back to the audience - she doesn't want to be seen/judged, but still wants to do her job (which is to sing her music).
Sia is classy and keeps her clothes on, for Sia it truly is all about the music. As much as I love Lana, her image has been fabricated by a team of people to sell a brand. Once Lana took her clothes off she became a sex symbol. Perhaps she gained weight to be more relatable to the majority of average-sized women. This goes along with my theory of why Ke$ha was so popular and still maintains a cult following today. Her body and image is easily attainable... shy chubby girls see her being confident and crazy and think "hey, I can do that".