After thinking about it for a bit, it's interesting what the results are of doing this. For the first nine days, players will learn together, sharing increasingly complex levels step-by-step and talking about every new element as it arrives. It's a short, one-time cultural event that represents the evolution of the series and lets people explore the possibilities together. The player-designed levels will showcase the progression from simple to complex.
So if you want to engage with other players in the "early days" of Super Mario Maker then that's motivation to be active for the first nine days of release, and if you don't care about that then just pick at it when you want, or wait nine days to get the game.