[r00fus]

> if you want to pipe music from your phone to your car, wouldn't you rather use WiFi than a cord?

No for several reasons (and since I haven't seen a single car with wifi music built-in, I'm going to assume you're abstracting wifi/bluetooth here into wireless):

1) Wireless drains batteries and I may not have a charger

2) Wired = charge-capable, likely charging.

3) Wireless setup requires authentication and configuration, often from the car itself. My 2012 Sienna is a great vehicle that is comfy on a road trip for 7 ppl, but it's BT implementation is a godawful nightmare. Setup is required to be initiated from the car, and can only be done through voice, and when you're not driving (even by passengers). Also, it tends to "lose" configs every once in a while. Meanwhile, the USB port just plays whatever's connected to it (we use mainly iDevices, so not sure about droids) and the in-wheel controls work fine.