Do you mean to say that societal evolution is the most useful form of human evolution? If so, I'm not so sure. For one thing, not all societies are human, and even human societies, though made up of humans, are not themselves human. Perhaps you mean to say that society is the most useful product of human evolution. I suppose that might be true, but again, not all societies are human societies and we don't know what evolution will come up with in the future. Personally, I'd say human intelligence is more useful than social behavior, but I'm not very social so I'm probably biased.