Music is music, there is no difference between video game music and well, regular music.
Agreed. There is little reason to classify the music that accompanies video games as something different, as some of the highly revered pieces today were written for theatrical performances and films.
My wording could have been better I realize, but what I mean is that there are definable differences between a track from a game and songs. There are of course a few exceptions to those differences, but the majority of tracks and songs aren't interchangeable.
I actually agree that there typically are compositional differences between music that was created for the sake of making music, and that for accompanying theater/films/television/games. The music is a key part of the production as a whole, and has to work with the rest of the production or it otherwise creates a dissonance that feels awkward. (Of course, that dissonance might also be desired for effect.)
Regardless, I think that music is music. It's just one of the many forms of creative expression we have. :)