In a new interview with Fast Company, she's explained her decision to keep the record off of the service, calling it "insane":

"We’re all making it up as it goes, to be honest. I would like to say there’s some master plan going on [with the album release], but there isn’t. But a few months ago I emailed my manager and said, "Guess what? This streaming thing just does not feel right. I don’t know why, but it just seems insane"... to work on something for two or three years and then just, Oh, here it is for free. It’s not about the money; it’s about respect, you know? Respect for the craft and the amount of work you put into it. But maybe Netflix is a good model. You go first to the cinema and after a while it will come on ­Netflix. Maybe that’s the way to go with streaming. It’s first physical and then maybe you can stream it later."

We at Best Fit have rather enjoyed Vulnicura, and you can read our review here, where we give it a near-perfect score.