This may involve the murder of the clone for the benefit of the original. This idea is comepletely unethical. I would rather die than bring someone into the world just to end up killing them. Cloning of humans would also cause mass hysteria with doubles and triples of everyone walking around. It is often said that doctors play God when making medical decisions but this is the true meaning of that phrase.
Nature does it frequently.
The value is this regard inestimable. Still, we should take things in logical order and exploit this technology first for wisdom, then for profit. In our current state of ignorance about the meaning of evolutionary genetic diversity, I don't see a current advantage for clones to improve our ability to survive or to insure the survival of the species with whom we share the planet. A monoclonal population would be far too susceptible to disease and other biological chaos. Plague and cancer have only killed a fraction of the world's exposed or triggered population for this reason.