The fiat currency is just as valuable as the lithium deposits because the fiat currency is backed by the most powerful force of military might the world has ever seen. When you trade for a dollar you're trading for that. Better than them just taking the lithium, as was the old way.
Empires that over-expand and seize too much sow the seeds of their own military destruction. Economic empires backed by ever-increasing military become overwhelming and then define any pushback as terrorism. What you end up with is a planetary-scale protection racket. Please do not construe this as an endorsement of other would-be hegemonies.
That's like saying fiat currency is just as valuable as lithium deposits. It's the hubris of the West.