I had mine set up like this before, but it bugged me that the radio display didn't have the song info, and you couldn't really control the songs as well through the radio. I use the USB connection more, because of all that, and because it also charges my phone. On longer trips, where my phone is also a nav and other duties, the battery charging is nice to have.
But that's just my choice.
2010 Stock IBM 2SS/RS
I found $80 in my jeans pocket. The kid in me said "buy nerf guns and candy!" But then the adult in me said "buy vodka, nerf guns and candy!"