It's called a remix ep. Lots of artists put them out when they release singles (Beyonce, Britney, Lady Gaga, etc)
Hopefully this means that they are going to promote Mirrors and send it to radio
What's the point of releasing this? Adds and promo for God's sake!
Oh my gosh, it's just like a remix EP. Almost all artists release them to iTunes when they come out with new singles. Meaning that she is probably going to promote mirrors.