Earlier quoted context omitted.
> If it is CC-BY-NC then he should be able to prevent you from adding ads in combination with his music I would recommend anybody not to license in a CC license that includes "NC" as long it is not clearly defined what you mean by "commercial". - Is using the music in a private YouTube video commercial (probably not)? - Is using the music in a private YouTube video that, say, some 3D-Designer rendered for a classroom…
These are all reasons not to republish -NC- material, they are no more convincing reasons not to use it to license as the arguments against GPL3. Maybe you have less uptake from people in the grey areas and less spread through for profit use. Looking at OSS today, maybe that is what you want.
The GPLv3 defines rather exactly what is allowed and what is not. That's what a license is for: defining exactly what is allowed and what isn't (which does not contradict that there are purposes for which the GPLv3 is suitable and ones for which it is not). NC for Non-Commercial in Creative Commons on the other hand is some wishy-washy term that does not clearly define where the boundary between commercial and non-commercial is.