I think I get it in a couple of sentences for the lay person.
Buy/Sell/Trade shares in your favorite bands, artists, groups with the tokens that are created by those bands, artists, and groups through bitshares music DAC.
Buy music through peertracks & possibly cash in some tokens if the band declares 1 token is worth 1 download or something.
I believe, the plan is the token holders to get paid whenever somebody buys a song. In that sense you get paid more when the band sells more songs, as opposed to the price to be determined by the bands themselves.