Those countries that built up precautionary reserve holding were able to avoid large depreciation in the “Panic of 2008” (Obstfeld, Shambaug, and Taylor, 2009).   The argument for compositional irrelevance of capital flows stands questioned. A recent IMF paper 2 has concluded that the appreciation effect of private flows differs by type of flow.
The difference lies in whether the benefit can in some sense be captured by the innovator, or whether the benefits are more dispersed and dependent on coordinated action. Payments service providers are good at proprietary innovation, as you would expect – they have an incentive to be good at it.