The BeoMusic app requires one of the new audio products (BeoSound Moment, BeoSound Essence or BeoPlay A9) to be present in order to be activated.
The BeoMusic page shows the supported products, for the app to function: http://www.bang-olufsen.com/beomusic
If other NL products (e.g. BeoVision 11, BeoVision Avant) are in the system, they can be controlled as part of the multiroom offering, but to a more limited extend (e.g. you can distribute sound to them, but you cannot fully control their sources). However, the requirement is that one of the previously mentioned audio products is available, for the activation of the app.
This is done due to a combination of technical and commercial/licensing reasons. I hope this clarifies.
Petros