I do know it has a use, just that the use isn't really... useful, I guess. It's more, sure, we can figure that we need vines to get to the cave, but it was only luck that I'd interacted with the vines in the first case (and only because I thought I could climb those ones). I didn't even notice the first vines you come across as anything other than decoration because, well, they looked like decoration. It was lucky chance I clicked on the others. Which is why I recommended they light up interaction-based things in the area - because that way you'd be able to figure out what can and cannot be interacted with. (I would have found the spear a bit easier, noticed the vines, seen the jawbone, etc.) Only my pedantic need to click on stuff saw me through the game.
Just, you know, pointing out that it's easy to get stuck in the game and not know where to go or what to do next since everything looks like decor and is easy to miss. It's an idea is all.