The time travel aspect was an essential part of the game and its main selling point. You only had 72 hours to save the world from a freaky looking moon that was on a collision course for earth thanks to the Skull Kid that was being influenced by the Majora's Mask. You used the Ocarina of Time from the first game in order to travel back three days to Day 1 to give you more time making it unique among other Zelda titles and horribly underrated as the years go by.
In this case it most likely is just a gimmick as you said to make more money (and it will most likely work) but it's based on a formula that has been proven to work and it comes as no surprise as XIII has already dealt with time travel.
As for the actual controller... it looks like something WCW would have made and called the Hollywood Hulk Hogan Controller.