I like to listen to podcasts or audiobooks while I drive. Usually I do this through Bluetooth.
Occasionally I want to use Android Auto so that the maps will show up on the car's screen. I have to plug in my phone through USB to make this happen. The audiobook will now play over the USB connection.
When I disconnect from USB or when I turn off the car, it switches from my audibook to SiriusXM ads. At twice the volume. It's incredibly obnoxious.