These are niche enough use cases I don't think they're worth bothering about.

I wouldn't dump millions into a custom GPS solution for that 1 time out of 1 million someone drives a car without a smartphone. Especially when that GPS system is guaranteed to be worse than Google maps and not as well supported.

If someone else drives your car they can connect their phone. Which is an improvement, because now they have THEIR music and navigation. See, it comes with personalization out of the box and automatically!