Ok so I just got it and man, what a bargain. OMG, what a difference it makes to audio quality! I used to have an AUX cable connected to lightning/audio jack dongle, and that sounded ok, until this came along.
Allows steering wheel control to skip track and raise/lower volume, but that’s it. Again, better than AUX cable and it’s even more limited controls (volume only). Although it defaults to the music on your iPod mode (or built in Music app in iOS) it will happily relay any output eg Spotify and allow same skip track controls too. Nice.