That last statement is not actually correct. In fact, 37 currencies do nothing to aid the blind in identifying different denominations, but the US dollar is the only major currency to do so. All other currencies either have different sizes for different denominations, some sort of raised features, or both.
But there the US dollar is, alone among the major currencies in being difficult for the blind, in the same company as Liberia, Zambia, and Turkmenistan. Even the North Korean Won and Malawian Kwacha have features that aid blind identification. Heck, even the currencies of fake countries like Somaliland and Transneistria have features that aid blind identification!