This is an interesting concept. I suppose you could do similar things with USD as well. You could declare, "Anyone with a dollar bill with this specific serial

This is an interesting concept. I suppose you could do similar things with USD as well. You could declare, "Anyone with a dollar bill with this specific serial number now has control of my company." I would argue that the dollar bill still has a value of $1 by itself, but you can assign arbitrary value to it by making it representative of another thing.