Why does Google need hardware patents?

[xchange]

If they're selling their one and only smartphone hardware manufacturing dept. then why are they keeping the patents? I can think of a few reasons,

1. They're just keeping them as another part of their overall portfolio purely for income from licensing
2. Because of all the patent wars
3. HW patents are still needed for their other devices like Nest and Chromecast
4. A just in case measure for the future
5. They're secretly planning to make their own hardware

Personally I believe the answer is most likely the first and second. Any other ideas?

 

[Citizen Coyote]

2, 3, and 4. Google has never shown an interest in monetizing their patents, they use them defensively. As for 5, I think the sale of Motorola and the rumored detente with Samsung discounts that.

Edit: that's not to say that Project Ara won't come about.