Home field advantage-if a game goes to OT, the home team gets the ball first. In the playoffs that means the teams success in the season has earned them a advantage in that particular situation. Regular season not so much, but its still homefield advantage. It's a similar vein to MLB, where if the home team finishes an inning ahead, the other team doesn't have another chance, creating the potential for the walk-off which excites fans and in now ingrained in the fabric of the game.
-M