I've had experience with this sort of tech before (as I'm sure many of you have) My dads Audi, 2004 model, has a sound setting called GALA, this in turn raises and lowers the volume of the sound system depending on the level of noise inside the cockpit. One thing is for certain, when you slow down to stop at the lights and your loud music suddenly drops and goes quiet it is beyond infuriating, one has set the volume one is comfortable listening to the audio, one does not wish it to change. If used for the purposes of raising and lowering audio volumes for music or video playback this will only prove to an enraging feature for me which would have to have an off switch.
However I am a fan of the idea that if I have my phone on ringer and the volume is set too low for my surroundings that it can intelligently give a greater output to be audible.