I think that actually experiencing the storyline for yourself, as in playing a part in it and doing quests that affect the outcome, is way better than a 1-and-a-half-minute video explaining what happened.
New players won't get to experience the things like Dalamud getting closer with each path, the weird weather, subtle landscape changes, etc. You'll be able to say you were there when the Garleans attacked. All the new players get is a video.
