Visa is an abstraction of my money. A better example would be american express gift cards. I can buy american express gift cards, and I can trade these gift cards or goods or services. The gift cards have a non-static real-value that is tied to the United States dollar (it's value in GBP, for instance, will fluctuate based on currency values).
I can take $100 USD, give it to a third party to hold, then slowly spend it as I see fit (effectively).
How is doing this with gold something that they should have covered in "high school economics class"? (No high school I've ever seen or heard of teaches an economics course, by the way)
I take $100, and give it to somebody who gives me an abstraction of that $100, gold.
To me, this sounds like literally the exact same thing as a gift card, just shinier.