What are the reasons the creator could not just re-upload the video as a new video? I don't use Youtube as a creator, so I can only guess. Links to it from ou

What are the reasons the creator could not just re-upload the video as a new video? I don't use Youtube as a creator, so I can only guess. Links to it from outside of Youtube? 'Millions of views' type of stuff? Ad revenue? Getting their account perma-banned?