[TuringTest]

>A human rubber-stamping code being validated by a super intelligent machine is the equivalent of a human sitting silently in the driver's seat of a self-driving car, "supervising".

So, absolutely necessary and essential?

In order to get the machine out of trouble when the unavoidable strange situation happens that didn't appear during training, and requires some judgement based on ethics or logical reasoning. For that case, you need a human in charge.