The point is completion. You may not physically require all the Pieces Of Heart in this game but I collect them all to fully enjoy every Zelda game.
Okay, I'll admit it...I missed some in Minish Cap because of the Kinstones or whatever they're called.
Still, typically, I don't see why you wouldn't get every Piece Of Heart in every Zelda game you play.
For all you non-completionists, why don't you feel the "itch" of an incomplete file?
(That reminds me, I have to finish Rollgoal.) In Pieces Of Heart, especially, you can always see an incomplete Heart meter, so it's not like some pointless side-quest that you can pretend you did even if you really didn't, and it's rarely frustrating to get them all. To me, it'd be like doing a jigsaw puzzle, and even if you can physically tell where the remaining two pieces are, you don't bother to put them in place. o_0 Why not complete it? WHY NOT???
Or am I just too obsessive-compulsive?