I'll go against the grain and say that there's not really a good reason for China to still use the death penalty. The arguments for rehabilitation and against punitive justice hold true in China, too. But when you compare it to what you see in the majority of criminal justice systems in the Western world, which is rampant brutality and exploitation of the workers and a free-for-all for the rich, China understandably looks much more appealing. I think eventually China should reform their punitive justice in favor of rehabilitation, but it's not my place as a westerner to set the schedule for that or make demands.