At the point where merge is possible, human + machine will probably already be inferior to machine only, in other words human would only make machine worse. Or

At the point where merge is possible, human + machine will probably already be inferior to machine only, in other words human would only make machine worse. Or at the very best, the human+machine period will last for very short time. Example is chess - there was a brief moment, where human using computer would outperform computer alone. That moment passed and that's it, humans can only weaken AI.