What defines a device?
Is it just a small electronic like your iPhone and iPad? In the latest 4.3.1 update of Xcode, Apple’s development tool, the device tab of the Organizer has a Macbook and iPhone as it’s icon. The tab’s icon has been an iPhone device since the Xcode 4 update.
Nowadays, most people wouldn’t consider a laptop as a “device” at first thought. However, Apple has been trying to make OS X and iOS more alike over the years. Most obvious with the announcement of Mountain Lion, the next version of OS X, which incorporates many iOS like features.
It is also interesting to note that the Macbook icon has the OS X Tiger Aqua background image. I’m guessing that the textured blue background is more visually appealing than the Leopard Aurora or Lion Andromeda background.