There was no point to that slingshot, I think they just threw it in for the nostalgia. You use it to get some skulltulas off a wall and then you get the boomerang in the first dungeon then bow in the next one and never bother with it again.
Maybe that's the reason Adult Link can't use it in OoT.I suppose it was just weird how weak it got even though there should be MORE power put behind it when you're a somewhat adult opposed to when you're a child, and yet its a weaker item. Just didn't seem to make sense.
Did anyone seriously use those things? I always had a full stack to be honest :/