Getting them to actually do something useful other than generating text is still a work in progress. What do you envision them actually doing in this integration?

"Killer app" in the good way or the bad way?

I've been saying hey google drive home (for GPS directions), and play music, to the phone mounted on my dash for a decade. I drive a rusty old stick shift and alligator clamped a $10 bluetooth to the speaker. So I'm not sure what you're envisioning that can't also work on any other car. There is also https://comma.ai that adds self-driving to hundreds of newer cars via just a ODB2-like dongle and equivalent of a smartphone.