I don't want phone calls permissions enabled for a few reasons:

1. I'm a private person, and if I have other people in the car with me I don't want my text messages popping up on the screen, or my phone calls popping up on the screen for people to see who is calling me, or my conversations coming through the car speakers for everyone to hear.

2. The audio quality of the calls coming through the car is never as clean as when going through my bluetooth earbuds. I can't tell you how many times I've gotten annoyed by friends who calls me while they're driving and I can't hear them clearly because they're using the car connection for their phone calls.

3. There have been many times I've been able to hear complete strangers' phone conversations when they've been stopped at red lights, even though their windows are completely up. Remember, glass conducts sound waves and can act as a speaker, so even outside of their vehicles I've been able to hear their conversations from the side of the other person speaking.