The fact that Asimov, who wrote this before computers and certainly credit cards were in existence is almost impossible to believe. Neglecting the fact that we know now that computers need not be huge in order to do great things, Asimov was almost unwittingly accurate in his portrayal of human nature. He reasoned, based on the technological advancements of his time, that humans would eventually create some sort of a machine that would destroy the imperfection of human error. However, he also shows that no matter how big, how accurate, or how formidable the machine, it is only as good as the data that is fed to it. This fact could not be more true with our modern day devices such as GPSs and military drones. We assume that since it is a machine that is giving us directions, and not a human, the data is infallible, and often pass up the opportunity to exercise our own good judgement in favor of blindly following directions. Multivac is not only the greatest computer in the world, but it also symbolizes all of our modern day devices that "eliminate" human error. What Asimov is trying to convey is that if you are willing to blindly trust a machine, your better off flipping a coin. Swift says that he uses an older way to determine his decisions, implying that the odds were the same either way.
Another use of symbolism is the fact that humans now don't even use physical money, and instead use electronic currency. This shows that not only is Multivac a machine used for military purposes, but it rules every aspect of people's lives as well. This form of electronic currency strongly resembles technology today in that it rules every aspect of our lives, from how we perceive the world to what we spend our free time doing. Asimov insinuates that complete reliance on technology will get you nowhere, but reliance on human intuition can win wars.