I don't think he really knew much about the iPhone when he posted that comment ^^
If he means he can listen to music while using other apps like browsing the internet then all I can say is that the iPod app (what most sensible iPhone users will use to listen to most of their music) can be run in the background while using other apps like the browser. Unless the iPhone user is hell bent on using the spotify app then I dont see a problem as the iPod covers it :S Spotify isn't really the most well renound app on the appstore and I don't think many people would turn down a phone because of that feature but you know