The value of re-creating mammoths might consist largely in satisfying intrinsic human curiosity. But, creating or re-creating some kinds of life forms may also be of great instrumental value to human beings, say in blocking the emergence of pathogens, or in helping to ensure the continued existence of life on the planet.
What initially seems like a curiosity actually prompts a deep question about the role of humans in directing the future course of life on this planet.
Up until this point, human influence on the world has largely been destructive. But we are now entering a phase where our influence can be constructive.
We can now preserve species not merely by conservation of the environment, but also through the use of genetic engineering, synthetic biology, and other reproductive technologies.