Hi, the reason for the device is that for the application environment to really work, we have to go all the way down to the kernel. Now, we could have a virtual desktop environment running under OS X, or a separate bootable OS. The problem with both is that they quickly become 'geek only' solutions, and there has not been a single OS in the history of computing that has been successful that way. All the successful ones were bundled into hardware. It is a psychological thing, but also an experience thing, as we know which device we are targeting and we can work to make it good, plus it helped us defines things in the hardware that work nicely with the software (the full surface, edge-to-edge touch, and the chipset, for instance).