Hi
Alistair,
Having playlists on the phone and playing it around the house is something I've never done. So as I try to understand, you are playing music that's stored on your phone (MP3?) with your phone as the player. (?) And then, maybe, sending the signal out on Bluetooth to be played on varioius speakers. (?)
If I'm at all close in my understanding, then the only real advantage I can see to playing on your phone is that you can play the music in any room where your phone goes that has a Bluetooth speaker.
And then the B2 would fit in as a Bluetooth receiver. (?)