Better than USB:
Because the only media savvy and so for example. controlling MP3Playern stops working or blocked in smartphones to mass storage. And the USB controller in car radios usually need ever to have recorded the music on a disk or enter the middle on. With already 60 GB music at about 5000 titles in MP3 and FLAC most car radios are already at least as long as with list busy as it lasts.
Better than Apple docks: Because Apple wants Docks just go with Apple devices and look ugly if you have something in the car but nothing to do with Apple devices.
Better than Bluetooth: Because music through Bluetooth is noticeably worse than listening via cable methods and more battery from the player eats.
Par with In Vehicle built-up hard drive and Linux on nem single-board computers. Because portability vs. convenience.
Better than: Android in the car with irgendsonem cloud service. Because we have already seen everywhere has Internet and there is no mobile phone tariffs in Germany, is where not throttled by a bissl Traffic.