"Why would you pay for radio when pandora is free"?
Basic functionality controls like FF, REW, pause, song and show scrubbing. Then there's on-demand programs, downloadable shows that can be stored on the device (eliminates data usage), customizable music channels, and no commercials. AND, there's the exclusive content not available on any other service.
If one wants randomly selected music from a mishmash of genres and a miniscule library, have fun with your free jukebox service interrupted by commercials every few songs (commercials always go over well at parties). If you want a vast variety of content, including sports, news, talk, and commercial free music, including live sets by world renowned DJ's, then Sirius can't be beat.