> The United States is the only country that prints all denominations of currency in the same size. The US and Switzerland are the only two countries that use the same colors for all of their various bills. Needless to say, this sameness of size and color make it impossible for a blind person to locate the correct bills to make a purchase without some sort of assistance, or confirm that he or she has been given the correct change by the sales clerk. Even people with partial sight may have trouble distinguishing a $1 bill from a $10, especially if the bill is old and worn.

https://afb.org/blindness-and-low-vision/using-technology/ac...

From dealing with Euro notes, I like being able to look down at the money in the wallet and pull the right notes out based on color. With USD I need to take the bills out of the wallet.

Which is great if you are fully abled! But for folks for whom sight isn't as strong, additional aids (different colors, different sized banknotes for different denominations) are super helpful.

Not everyone can see.

Australian notes vary in size for this reason.

And it would be even easier to distinguish them if they were different colors in addition to the printed numerals.

This is a joke right?