The smartphone introduces friction into the concept of a “phone” itself. As a portable calling device, the smartphone is bulky and call-droppy and shattery (who makes a mobile device out of glass?) and, it must be said, noticeably unfriendly to the cheek. As a portable computer, however, the smartphone is elegant and efficient and — Mr. Jobs was not exaggerating — revolutionary. It’s a computer with phone functionality, rather than the other way around.