[ajanuary]

I think it's more justified here than aero, but in both cases it gives you a sense of context, that the other layer is still there benief it even if you can't see it clear enough. In a static shot it's just noise, but as you slide it up it reinforces the idea of layers.

That said, once you've slid it up it's just squiggly noise that's damn near impossible to draw type on legibly.