not only is a easy way, but it add so much to the immersion of the game, if i hit a mob and he falls in a hole, its nice to have he back there when i come back, the despawn should happen to mobs that did not Interact with the player as they don't add anything to the game, and give a chance to spawn new stuff.
its vanilla bd craft, don't know who the creator is, and textures that have animations on it, like clock, compass etc are glitched.