Obviously little buildings are not going to be adequate for everything like an orchestra or opera performance. So that isn't meant to apply to every single building.

But as far as practicing those things, generally there is sound proofing in those types of music practice rooms, and also I have suggested airtight construction with SIPs and HRV. This means most of the sound is insulated between outside and inside anyway without any sound proofing.

Also, this is partly an alternative to apartments or townhomes, where walls and/or floors/ceilings are shared. So obviously an advantage there even without the advanced construction and ventilation.