- Leveraging current engineering projects
- Reducing manufacturing costs
- Simplifying the product line
- Staying reasonable in terms of product costs
- Stick the guts of a MacBook into an Apple TV sized case
- Drop out the LCD, the battery, the keyboard, the DVD
- Drop in a (cheaper, bigger) 3.5 inch HDD drive, in lieu of a 2.5" notebook drive.
- Add various Video Out options
- Provide a standard MacBook power brick
Of course, this computer has USB, Firewire, Bluetooth and 802.11. So there are no limitations in terms of adding peripherals or storage. Need a DVD? USB or Firewire is there. Plus, this device would have two video-outs. With suitable dongles, you can send video over HDMI, DVI, Component, VGA, and even S-Video and Composite.
I agree that both the Apple TV and the Mac Mini aren't going to be around for much longer - in their current form. But I think its because they are evolving back into a more capable computer that could leverage Apple's pre-existing efforts.