(See also my initial thoughts.)
I wondered why the latest Apple devices, including MacBooks (especially the Air), iPhones, and now the iPad all have rounded backs/bottoms. Well, the answer is very simple: Remember the last time you had problems picking up change from a counter? It would be nearly impossible to pick up a 700 gram (1.5 pounds) metal slate lying flat on a table without being able to put a fingertip under it:
It’s so simple that you don’t notice. Like some kind of industrial design typography. Sure, it doesn’t look nice from the back – but who cares? The only important part is the front.