Sure, they have 5 hp each... but any time or attention the enemy devotes to killing totems, he is devoting to not killing you. Against most enemies, you are up close meleeing them, which means they can't exactly turn away to deal with totems. (Hunters especially, since they have to put up their bow when you start hitting them with your axe.) Against melee classes, chasing your totems means going away from you, allowing you to kite them. Plus, totems aren't the easiest things to target. Yes, totems rock even in PvP. To make things harder, drop totems and then maneuver yourself away from the totem drop point. That means that they must physically turn away from you to chase the totem. Advantage: you.