It sure would be great to have the ability to play more than one playlist at a time. I have playlists that represent subsets of an artists work that might be, say, just instrumentals. These subsets might cover several albums of a single artist. The thing I can’t do is listen to instrumental playlists over several artists without creating more playlists.
In other words, playlists allow for customization of music, but as far as I know, the sansa fuse 8 can only play a single playlist at a time.