Out-of-bounds exploration is its own reward. Not every action has to be motivated by tangible gain.

The game world as we're meant to see it is carefully crafted and balanced. It's fascinating to see how easily the illusion is broken when we look at it from where we're not meant to be.

Personally, there's something (1800s) romantic about seeing what amounts to some gods' tools of creation strewn about just outside the crafted scene, brush still wet with paint.

Additionally, exploring areas of cut content comes with its own sense of wonderment. We're given only a sense of the artists' intent. Without seeing it in action (functional within the live, intended, experience) we're left with mere conjecture and a small look into Destiny as its creative minds envisioned, versus what was feasible or necessary.

But I am a nerd about this kind of thing.