Gold is a “relatively soft metal,” and if you chomped down on it, you’d get a similar indentation to what you might find if you bit into a chilled chocolate Easter bunny. So, back in the day, this was the quickest way to see whether you were actually winning something of value, or if it was merely milk chocolate wrapped in gold foil.
These days, of course, the practice has taken on a life of its own. David Wallechinsky, president of the International Society of Olympic Historians, told CNN that “It’s become an obsession with the photographers. I think they look at it as an iconic shot, as something that you can probably sell. I don’t think it’s something the athletes would probably do on their own.” So basically, it’s “the money shot.”