They also use forex reserves as rainy day funds to help countries during times of national or international economic crises.

FORBES: China's Cash Position Swells To Record High

In other words, the forex reserves argument is largely an illusion.

FORBES: Why A China Crash May Be Imminent

Of the three approaches, methods 1 and 3, using currency shares and empirics respectively to adjust for currency valuation effects, result in robust relationships between changes in currency-adjusted FX reserves and the BOP surplus, whereas method 2 using forex purchases as an alternative proxy for adjusted FX reserves is inferior.

FORBES: How Much Longer Can China Accumulate Reserves?