Money replaced barter. Like gold it is as powerful as common consensus dictates. If we were all to agree that it was worthless then that is what it would be. diamonds are different in that they have a value outside common consensus. They are hard therefore have industrial applications beyond whether women wish to wear rings and necklaces with diamonds or not.
If anybody thinks money is powerless, just try living without it. Every culture throughout history (bar the most primitive) has had some kind of medium of exchange. If you took money out of the equation you'd have to go back to a society where people don't travel, grow nearly all their own food (and barter the rest) and generally subsist on as little as possible.
As big an advocate as I am of living frugally, I wouldn't fancy this type of lifestyle much.