I think the joke goes something like Darth Vader has an ATM on his chest. That's actually total malarkey, because it truly is a piggy bank/safe for keeping his wallet. Heck, if you're mostly robot you might as well have them take out all of those pesky internal organs. One's chest cavity can contain a lot of things! Much like a Bag of Holding or Bender's chest in Futurama. The possibilities are endless! Darth Vader can be said to have adopted a 'live by the sword' mentality.

Hey, those Sith Lords are bred on violence and fed on seething contempt.  Do not look to them for compromise or anything resembling compassion, unless we are talking about mercy killings...which they are fairly liberal with! Are you a Sith Lord? Are you a Star Wars fan? Need a new wallet? If you are at least one of those things, might as well take a look-see at this Star Wars Vader Crossed Sabers PVC Wallet. It won't let you lead your friends into a trap or slice off your hand because of unresolved father-son issues.