living in japan, it's pretty easy to find video games such as dance dance revolution, pop'n music, and guitar freaks, drum mania and beatmania.
actually "easy to find" should be replaced with "impossible to miss!".
likewise can be said for their soundtracks. you can go to any store that sells music, and find a song from your favorite dance/beat related video game.
oddly enough, this so-called "video game music" isn't made just for the game.
for instance, in beatmania 4, you can find a good song titled "the race" by an artist known as captain jack.
captain jack doesn't make video game music.
he makes dance music.
i have 2 of his cds.
basically, this is a remix of a real dance song here in japan.
i don't think this blurs the line.
i think it crosses it completely.