This is a stupid (or desparate) move by Starz, but it also shows the weakness of Netflix: if you rely on someone else for content (same goes for API) for revenue, theye can screw you up (e.g. there goes 11% of our valuation), even if it's in the short term. I think Netflix should be more aggressive in creating own content (key to HBO's success). They are already moving in this direction but very slowly. Why doesn't Netflix outsource content (to film & journalism schools or just YouTube era amateurs) and stream it theirselves?
The real question in my mind is "what is Netflix bringing to the table?" I mean, there's no reason Starz can't set up its own download channel right next to Netflix and Amazon on my Roku, is there? Why should they give Netflix a cut?
For Roku, at least, I think the way it works is you give your credit card once and then you select channels through Roku. So in this case it's not any less convenient.
It made sense to go with Netflix when nobody else really had a streaming implementation, and Netflix had its own advertising the content providers could piggyback off of. But these days more and more people are getting content through third party boxes that already act as payment processors.