I always thought it was a bit overplayed, honestly. You see it on covers, in tattoos on a don's hand, used as a signet ring. To me, it's shorthand for the whole 'death before dishonor' code these characters are supposed to live by, but it also highlights the irony. They're walking around with this symbol of mortality, but they act like they're untouchable. It's a reminder that in their world, your life can be forfeit over a single mistake. The skull isn't just about threatening others; it's a constant memento mori for the wearer, too.
In some of the grittier series I've read, like the ones set in Naples or Eastern Europe, the imagery gets even darker. It's not a polished, stylized logo; it's a rotten, fractured thing. That feels more honest—showing the decay beneath the power suit. It symbolizes the rot at the heart of the 'family' business, the way loyalty eats its own. A gold skull ring on a clean hand feels like a costume. A crude tattoo on a scarred knuckle feels like a brand.