"I don't think a blind/visually impaired person can feel the difference in size of the banknotes. You would need a ruler, or at least sort the bank notes by size to feel the difference. But some countries have tactile marks on their banknotes."
I tried an experiment. No 50s but I closed my eyes and mixed up 2 20s, 2 100s and 2 1000s. I was able to put them in order relatively easily. Wouldn't take long to just know which was which by feel.