What are the hookshot ledges for?

I noticed areas on Legend Mode maps that are only accessible by Hookshot, much earlier than when you actually obtain the Hookshot. For example, there's one in the north of Hyrule Field, the first area of the game (and, if you're just following the story checkpoints, it's quite far out of your way). There's also ones in Eldin Caves and Faron Woods.

Naturally, I assumed there'd be secret goodies for players who came back later after getting the Hookshot and climbed up there (a chest, perhaps) - but after returning later myself to do just that, I found the area above completely empty.

Is there ever anything up there? Does an event need to be triggered for something to occur? Or is it aways just empty?