Reading through, it makes me wonder if it's more gimmick than substance. At the ~$500 price point, you can step into some strong P&S that have a sizable sensor, can shoot RAW, and offer more (and better) options.
The $250 price point replaces the larger sensor with a much smaller/weaker one and replaces the glass with lower quality stuff, turning it into something no different than a similarly priced P&S.
(Edit, I stand corrected on the sensor stuff. I'm not entirely sure why I included that in the final post, since it was something I wasn't really sure on.)
I'm a bit skeptical about the WiFi transfer, both for images and for the viewfinder/phone itself. Without using the internal storage, it seems like the WiFi transfer of images should nerf the burst rate considerably. It's possible the buffer size was increased to compensate, but I wouldn't hold out much hope. Even more so, since images can stay on microSD cards within the "camera", the latency of the WiFi-based viewfinder (your phone) seems like it could hold potential issues (especially if the app isn't working right or there is lower O/S support than it needs to have).
Likewise, the build strength seems like it could be another potential pitfall. It would necessarily be quite a bit more flimsy than a standard camera, as the phone has to remain removable. The "grips" onto the phone will hopefully be very solid and not wear out, leading to potential "slide-out" of the phone and down onto the concrete. At least I did buy the insurance for my phone! (Note: normally I wouldn't but both of my past phones have had some issues that would have been covered (crazy possessed touchscreen, USB port dying), so I went for it with my new one...)
Lastly, this image:
(From the technical specs page) makes it seem a bit bulkier. Of course, it looks like that's with it zoomed in a bit, but even out to the larger cylinder doesn't appear to be saving much bulkiness from a equivalent P&S.
Now, I'm not all down on it, assuming that it's possible to hold the phone and lens apart from each other (since it seems like it's only a WiFi connection), it could lead to some interesting compositions as well as easier control in more awkward situations.
The WiFi issues I have could also be remedied with accessories (namely a wire), which that plus adapters could also add a larger margin revenue stream.
Of course, I'm also heavily biased against people using smartphone cameras for anything short of quick snapshots. And I heavily dislike instagram
, so I may not be the best judge here.