Don't look at this app as a musician's tool or as a toy. This is a Steve Roach long-form atmospheric piece.
As opposed to a CD, you can adjust the mix & panning of the 5 stereo stems if you choose - or just pick a mix from the menu or let the parts randomly mix themselves. It's really just a different way to experience a long-form track - with the option to control the mix.
Another aspect to consider is that due to the crazy-low app pricing "standards" these cost only $3-$5 each (with no shipping costs) for a long track.
I just bought the new one yesterday and from limited listening, I think it's my fave from the series so far.
I think it is more fun for non-muscian actually.. personally I just do find myself want play around with that app just to merge some loops... but I can understand people who do it though...