So if you want to play your own music thru your car speakers, and you want the bluetooth on your phone to connect and come out of the speakers as well, and you still need another cigar lighter socket to power your Satnav, then this piece of kit will do it all!
It looks as if the SD card sticks out of the side in the photo but don't worry, they just did that to demonstrate the concept, it doesn't stick out at all, so there's nothing to get broken off.
The only improvement I can think of would be to supply some kind of velcro based strap for the remote control, so you could fasten it to the steering wheel for convenience when selecting music and so on. Its not essential because you can do most of the controls you need from the cigar lighter part, but hey, I'm just trying to be helpful :-)