I think Voigt meant to type "you cannot manually save using the button" in Ironman games. That's an intentional change meant to prevent (or at least reduce) easily redoing mistakes or changing decisions during the course of the game ("save scumming"). Ironman games are meant to be straight-through, one-shot runs for the sake of bragging rights. Since you don't have to play them in one sitting, the game does get saved on exit so you can pick back up where you left off.
So, as Voigt points out, you could still save-scum if you were willing to quit the game right before making your important choices, or quit and reload frequently during the course of the entire game. Restarting the game of course takes a lot longer than loading a save. The higher cost to reload will dissuade players from doing so often, but it's not an absolute prohibition.