And it feels a bit more futuristic than the old nav-bars-of-square-buttons, in a Minority Report/Google Glass sort of way. Eventually, there might be a bunch of buttons hovering over our field of vision, on our car windshields, eyeglasses, wherever. This simulates that heads-up display effect.
Design trends come and go: some of them stick around, others are popular for a while but then slowly disappear as designers figure out better solutions. Remember when, after Instagram 1.0, dozens of apps started using large buttons in the middle of a toolbar? Or when pull-to-refresh could be seen in all sorts of designs?
Trends subside with time: new ones come out and gain traction, old ones re-surface with refreshed implementations. In the past few months, there seems to be a comeback of fun, entertaining pull-to-refresh animations after Apple's default take with iOS 6. Two examples: Twitterrific 5 and the just-released Twitter Music.
The iOS ecosystem is now mature enough that we can recognize specific design patterns evolving and changing with time. I agree with Dan's conclusion.