One big advantage you won't get is staying at Disney resort the night before. They take your luggage from your room and you don't see it again until it is outside your door on the ship.
The only advantages that I can think of is that Disney will take care of you is something happens on the way (traffic, accident, break down, etc.). I have heard that they will even hold the ship for you to arrive as long as they are able. I believe they would even get you to the next port of call if they can not hold the ship for you.
Actually, OP indicated they are staying at the MCO Hyatt, therefore they will get luggage service from the hotel room straight to the ship.