pay by value   (geekin)

Cash can be stolen and used easily. Cards can be stolen and used, but you can get the money back. Big difference.

Pay by value is much better than pay by reference.
If you lose cash, you lose the value, but no pointer escapes the transaction. If you pay by reference, you leave a trail of pointers around increasing the risk of someone dereferencing your wallet.
 -MillionthMonkey, Identity Thief Victim Gets Last Laugh