Yes, it will launch xmms if it not running, starts playing and opens playlist. You can remove the "play_list 1" if you don't want playlist to open. You could also add "main 0" if you want to minimize the main xmms window.

That is a good use for the first value. It could be used to set the governor to powersave and restore it upon exiting audio lock. Only problem is that powersave no longer seems to work on my device. Try setting powersave, then drag the ASUI window up and down and tell me if it stays at 165. Not sure if this is a DT kernel problem because it worked in the pre-DT days.