A copy is just an identical image. There is a possiblity that a virus could destroy an entire set of systems, and copies due not give rise to variety and originality. Life perpetuates itself through diversity, and this includes the ability to sacrifice itself if necessary. Cells repeat the process of regeneration and degeneration until one day they die, obliterating an entire set of memory and information. Only genes remain. Why continually repeat this process? Simply to avoid the weaknesses of an unchanging system.