A mobile becomes many things you need:
When more functions must be put into a single device; when a mobile phone tries to do everything, the solutions are always too complex. The functionality losses its familiar forms to communicate with users that result in difficult use and compromised experience. Arbitrary interface causes user confusion.
The Black Box concept is to recall and respect the classic long-time conventions and real-world experiences of using various common tools and devices; keep only the meaningful and minimal interface elements to fulfill the maximal user desires.
Back to classics. Back to basics.