I think that is interesting and useful.
Now if the Arduino IDE was running on the Pi, the extra features were added via the Boards Manager, and sketches wrote were deposited as executables in some directory on the Pi instead of "uploading" or transferring via Samba that would be fabulous. It would be similar to the way PCduino is supposed to work.
To take it one step further, having an option to run the sketch on the Pi as bare metal and only boot up Linux on the Pi if a particular IO pin is grounded, that would be even better.