The Obvious: It’s Going Away
Reasons to Buy Super Mario 3D All-Stars
This is obvious but it does need to be stated. As far as we know based on what Nintendo has said, once March 31 comes and goes there will be no way to buy Super Mario 3D All-Stars directly from Nintendo and, presumably, stock at physical and online storefronts such as Amazon will no longer be refreshed.
Nintendo could absolutely change its mind, but until we have evidence of that we’ll need to take them at their word.
If you wanted to buy Super Mario 3D All-Stars after March 31, you’ll have to either find stock somewhere at a store before it runs out or you’ll need to buy it second-hand off someone else, likely at a premium as time goes on.
Just save yourself the trouble and get it now before March 31 if you think there’s any possibility you would want it one day, even if it’s not right now.