BVH cache and how it works.

Hi there. Just a quick question on the BVH cache setting in the render properties.

i notice in my current test fly through animation a BVH is written to disk for every frame, is this because I have objects moving in the animation? If so, this isn’t really a very efficient cache system, as it eats disk space at an alarming rate for no purpose. Is this setting more useful for simple panning shots where no objects move?