If you look at it from the perspective of Amazons own internal wealth being its own currency, money has a different value in the system and outside it. He buy

If you look at it from the perspective of Amazons own internal wealth being its own currency, money has a different value in the system and outside it. He buy things directly with stock, like we would use cash. He can downgrade his value store from Amazon bucks to USD, but he doesnt have to to spend it. Knowing how Amazon shares convert to USD is probably less useful than knowing what you can buy directly with Amazon shares.