Large-scale reserve accumulation has significant costs at both the national level (in terms of foregone consumption and investment, or quasi-fiscal deficits incurred when reserve accumulation is financed or sterilized with debt offering higher yields) and the global level.
In practice this meant either that the domestic currency public debt would have to increase by the amount the authorities were willing to intervene in the foreign exchange markets, or fiscal policy would have to adjust to find the resources for foreign currency purchases out of current spending or from increased revenue.