It really does make CUPS, Libre Office and all the rest believe you when you say "I want to print on A4, yes A4, no not fucking Letter, A4, end of!" Obviously, substitute your paper size of choice. It probably even lends itself to some form of scripting and perhaps could be changed in reaction to events from say NetworkManager. Whatever.

My life at home is now worth living every time the wife hits print. Such a simple idea - brilliant.