Nature doesn't let anything go to waste, so why should we? The idea of a Circular Bio-Economy is to treat waste as a resource that can be used. Most of what we call waste can be broken down in a way for us to get something out of it. There is no reason why we shouldn't try to reclaim resources from waste products.
We are just starting to understand the machinery that drives nature. As people engineer around phenomena seen in the natural world, we create better technology.