I think it's a smart move to make the songs exportable. There will probably be a decent chunk of people who buy the game just to do that and never even play Blitz.
Overall, I'm more excited by the idea of this game than VidRhythm or Phase. The idea that it supports all existing DLC is another smart move to make sure it has some longevity to it. I'll try it and probably do my best to get its achievements.