It is of course possible that oppressive regimes may eventually target the devices. There are a few ways to reduce the risk. First, because the entire design is open, it would be possible to make versions in different form-factors, so that there is no single common version of the device to target. Second, as you suggest, it would be possible to automatically erase data on a device under certain circumstances. Again, because the design is open, a variety of different approaches could be used that could be device-specific, so that there is no single known trigger that they would try to avoid activating. In short, it is about as good as you can hope for, but of course nothing is perfect.
... I also meant to say that the game console form factor also has a number of clear advantages. For example, interacting via physical buttons is much easier than using a touch screen (which we also have) if your hands are dirty, wet or cold. Also, the console form factor is big enough to have a large enough solar panel on the rear to be self-powering in many contexts. So, yes, while some folks might feel that it is odd at first, my feeling is that it is still the right form.