Aristotle gives good reasons--scientific and ethical reasons--why we ought to value other natural things more for their own ends than for what we can do with them. Sure enough, humans need to use natural substances, including other organisms, instrumentally. The development of techniques of hunting, agriculture, and animal husbandry is a clear manifestation of that need. But Aristotle argues that these techniques, like all technologies, have a natural limit, the transgression of which is contrary to nature and ignoble. That limit is what is necessary for our survival and functioning, in acordance with our own natural needs and functions (which, Aristotle holds, can be objectively determined for humans, just as it can for other animals).
We have overcome the Aristotelian view that the earth is at the center of the spatial universe, but we still need to come over to the Aristotelian view that humans are not at the center of the axiological universe. Thus I think that a study of Aristotelian teleology, in addition to benig an intrinsically valuable exercise, can be justified instrumentally on the grounds that it has something to show us about our relationship to nature.
Monte Johnson, Aristotle on Teleology. Clarendon (Oxford: 2005), p. 5. Monte's book is reviewed by T.K. Johansen here.
