A monetary system requires ignorance, hidden information and secrecy in order to function. If we had perfect transparency in all market place dealings, then no one would be able to profit, and then there would be no need for money.
It takes me about 30 minutes to change the oil in most cars. It costs about $25 in supplies. I have no special training.
I'd bet you whatever you value that I could tell someone exactly that (perfect transparency) and sell them an oil change for $50. I would be profiting from the exchange.
Besides perfect transparency requires zero privacy. And I value privacy. It's none of your business what I possess.
Doesn't disprove the assertion.
I gave an example where I can provide someone perfect transparency and still make a profit by selling goods and services.
Money is just a tool. Anything can be money. If I trade Joe an egg for a loaf of bread, and then Joe trades that egg to Frank for a pair of shoes, we have a working monetary system using eggs as money. Where is the ignorance, hidden information or secrecy? Joe and Frank don't need to know where eggs come from, what I did to get the egg, or how much anyone else values the egg. All that is required is that the egg has value to them individually.
Do they have information pertaining to the quality of the items, their relative scarcity, the availability of the resources to produce the bread, the chicken population, the dietary needs of others, etc.