Most hands of poker are decided without showing the cards. Does that make the cards irrelevant? Of course not; everything that happens is conditioned by the probable outcome if there were a showdown, as judged by the players in the hand. Changing one player's hand could change everything, even if no one else ever sees it.

A change in the way verdicts are reached will be much more powerful, being seen by both sides. Therefore even if nothing is done about the plea bargain system (and something should be done), the key to the game is still the "showdown".