how are you supposed to get more of these to trade? "being a unique human being" just doesn't cut it for me, maybe I'm missing something? it all seems like a way to trade your identity for monopoly money
Same way you're supposed to get more of any currency: from other people.
The 25 WLD are just an initial gift, like a "universal inheritance", that's going to have a value anywhere from $0, to [total amount of money]/[total number of people] in the world.