Yes, if there is a danger that the koala will become extinct, then they should be saved. Everyone thinks that they are cute little teddy bears, but in reality they are a part of the ecosystem and they are wild animals. Some animals need more protection than others and this may be one on the saving list.
Koalas are threatened by a wide range of ever pressing changes to their natural habitat most of which are caused by human beings and our constant need to control and harvest the wilderness. If we continue to constantly disregard the needs of the koalas then some day they will not exist and our world will be worse off for it.