GDP is often fake, especially in hyper-financialized economies like the West’s which just move money around a lot without really producing anything, and it’s a poor metric for development anyway even when it is real, but even by the West’s own rigged standards China is beating them handily - and not just China, look who else is at the top of the list.
Yeah idk, maybe in a capitalist economic paradigm you’re right. Maybe the idea of pegging currencies to various (not necessarily a single one) commodities is to some extent necessary since bourgeois states are so addicted to just printing money. But under a socialist planned economy money is essentially a voucher that represents a certain amount of labor. The reason why it has value is because it is backed by the state. Which is ultimately where all currency derives its legitimacy from.
Even a gold backed currency is still just a promise from the state. The only alternative is to literally use gold or silver coins again, but the problem with that is that’s not currency in the way we understand it today. The value of each coin would depend on the momentary market value its material. That is effectively just a barter system with extra steps. It is why “cryptocurrency” can never be an actual currency. Anything that is a speculative commodity simply won’t work as money.