The only reason I can see it being on Heat (storyline wise) is if the winner will get a match later in the night on the PPV. Maybe they will add the winner to the Money in the Bank Ladder Match?
If it's on WrestleMania, maybe they'll get to choose which show they'll be on (if they're planning a draft), or they'll win a shot at their world champion at their brand's next PPV...
Or maybe they're just throwing this in there for the hell of it and the winner gets to mop up after Triple H and Vince...