Holt, the answer to "what do we need to live" is not merely the basics of food and shelter.
There's a saying "give a man a fish, and you have fed him for a day."
People need capital - a fishing rod; a place to fish; or perhaps farming equipment and a place to farm, seed, yadda yadda.
People rarely are able to grow and make everything that they need, from food to water to shelter to nails to housing to wool, needles, a loom, butter churns, and so forth and so on. In short, people need to trade.
We could just barter - but that is not easy when you produce "farm wagons" or "rifles" and people have limited need for those particular products - how do you continue to acquire groceries when all the farmers in your neighborhood are satisfied with their capital good stocks?
Enter "money", which can be defined as "the most tradable good." Many things have served as money - tobacco leaves, shells, iron, copper, silver, gold, sacks of wheat, barrels of oil. Some of these are not durable (wheat, oil). Some are not easily divisible ( diamonds, or Picasso paintings, for example ). Some are not scarce enough ( faith-based printed money, for instance ).
Gold and silver have held up well for thousands of years because they are durable, scarce, valued, divisible, portable, uniform, and identifiable. If you've ever held gold and silver coins in your hand, you'd recognize instantly that today's coins are cheap junk. Gold in particular is one of the densest metals known.
The main advantage of precious metals ( gold, silver, platinum, etc ) is that they can't be created out of paper and ink. Have a look at this image:

That Zimbabwe $100 trillion note is worth about as much as one egg nowadays.