It certainly sounds like a contradiction, but I suppose it comes down to how much time the driver has to take control "when prompted to intervene". If they are expected to take control in (for example) less than one second's notice, then yes driver must keep their attention on the road at all times.

If the car is able to recognize far enough in advance that it doesn't know what to do in a situation and reduce speed, pull over, etc., then that could be enough time for a person to put down their phone and take control of the vehicle.