Well considering that there was no muster drill before leaving Civitavecchia when the Costa Concordia accident happened, and many people were unsure what to do or where to go, I don't feel that it's ever in vain.
I've heard the shpiel almost 30 times now so snapping the photo is good enough for me but I believe especially for beginners, it's important to thoroughly understand it. Parents should emphasize the importance of paying attention to this to their children, the same way we do with bike helmets and wearing a seatbelt in a car.
No one expects something to go wrong but that's why we call them accidents.