while some new things are overkill IMO, not having to explain to a family how the untrained "captain" in the RHS used the wrong control inputs and flipped his aircraft after a cut at 50ft AFTO seems reasonable to me.
Take the average A320/Boeing twin. Both can be flown from either seat by pilots with a command type rating. . Presumably both pilots are current on the aeroplane having completed cyclic checks and have current IPC. The cyclics no doubt will have included engine failures after V1. if the pilot in the RH seat be he captain or F/O, cannot handle an engine failure on take off simply because his recent flying has been from left seat, then what does that say about the competency of the training system? And worse still about the competency of the pilot. As one contributor said: It is all no big deal.