Reasons to use it over my phone:
* 11" screen shows me a high quality map overlayed with current traffic, with 1/3 split for lane guidance when needed
* Directions also shown directly on the dash - no need to look far away
* Spoken instructions dim the music volume
* Pretty accurate traffic information with automatic OTA updates
Downsides:
* Voice control is shitty; saying "set destination to leamington spa" will change to a random radio frequency
* Slightly awkward to send routes from PC to car, has to be via Remote Control App