This seems like a nonsensical distinction between mandatory and optional triggers... especially because at its conception, golden cherubim was likely worded cbn to work when discarded by all the negat and dc cards lol Makes Habakkuk and Joab very lackluster also. It would make sense to me to reassess that rule in the REG. What is it about an optional trigger that makes it not work when out of play? How does the card not being in play imply that you choose to not use the "may". Because all that is obvious about optional triggers is that it is ongoing and you get the option to uses it or not when it triggers.