You make a huge assumption that "natural" things are designed by God.
The point here is that biological evolution is a design process in its own right, but one that differs fundamentally from man-made designs. That's because man-made objects all have a function, even if this is to amuse or decorate (arts and crafts) or change man's mental state (painting, music, drugs). A can-opener satisfies these criteria. As pointed out by Darwin, no organism can develop traits that are solely of benefit to another organism, yet the can-opener benefits us without benefiting itself.
Creationists tell us that God created the Earth and designed it to be a good place for man to live. Then he gave man dominion over it all. Man was to be a good steward of the Earth and its resources. So the
creation of man is his purpose, his
redemption his purpose and his
destiny his purpose. God wants some obedient righteous people so that they can live with him forever... But isn't the Earth then just temporary accommodation?
Is that it? I personally cannot accept this gross expression of
anthropocentrism, so I'm left thinking, from the point of view of the 'intelligent designer', what the objective of all his hard work is? What is the point of the objects (billions of living organisms) that he has designed? What are their functions. For example, what is the function of a rabbit — is it to feed the foxes or keep the grass short? What is the purpose of the Universe? What function does the Earth play in the Universe? Is it really only to show man the power and majesty of God?