Never understood the rationale behind getting cc involved in reading checklists.
They are not familiar with them, often don't know where to find them on the card, stumble over reading/pronunciation and have no idea if the response is correct or not (beyond what is written which is merely the verbal bit and not in any way a check that the acton has in fact been executed), can have virtually no input in monitoring anything at all and are thus surely more likely to increase the PH's stress levels than doing it himself, unless it is to make him feel less lonely.
I wonder if it is more a product of doctrine that checklists are only "safe" if two people are involved rather than a practical aid to a single pilot landing when surely you can rely on the remaining pilot to be at max alertness in getting things right?
I always found it a severe pita when handling this exercise in the sim.