If you make a fresh piece of gold and show it to the world, you are proving that you have done some known — or at least bounded — amount of work.
In gold’s case, that work is gas, electricity, and human labor. If someone shows up with gold that cost less to produce, the price goes down.
Work for the sake of work is not valuable.
You could record video proving that you dug a hole 20 feet deep with your bare hands and then filled it up again.
That's a lot of work, but it wouldn't be valuable to anyone, except maybe as comedy.
https://www.theguardian.com/technology/2016/nov/28/cards-aga...
However, should it be impossible to copy videos and the only way to do a video would be to capture the events as they happen, then perhaps your video would have value.
Making origami pirate ships also requires a certain amount of work. That doesn’t give it value.
Imagine what would happen if one person held literally all the money. It may be easier to imagine a 100-person community rather than the whole world.
One thing that would have to happen is everyone else would develop their own money/currency, which would turn mean that the one person with all the money is no longer the one person with all the money.
A thing quite likely to happen is that everyone would decide that whatever the money is that the one person has, everybody would decide it is not money.
It isn't entirely dissimilar from me claiming I have all the Jerfoleans on the world, and what the world is really doing about that currency right now. They're worth a zero so zero-y that even an infinite number of them is still worth a flat zero. Someone who has "all the money" might find themselves in a similar boat.