Not convincing. If you mean the game art as a whole, then yes. But if it's just one part, while lot's of others are already under ABC - then it's not reasonable. I.e. if you use some art which is under CC, still other games won't look the same, because it's just one part. If the whole content is CC, then game is easily cloneable as is. But lot's of parts are already ABC, so game isn't cloneable, and using some CC parts won't hurt anything. I also suspect the ABC limitation scares away some potential artists as well, so the intended benefits can be outweighed by the stronger drawback, which is - no artists.
