Never really given this much thought to be fair, but with the invention of smart and touch screens mobiles have become unusable for the blind unless you had the Voice over apps
Thinking back to the old keypads, they had the dot on the 5 so a visually impaired person could navigate it but naturally you don't get that on an iphone.
My great uncle was blind and as a child was always fascinated by his ability to read braille, wonder what he would have made of these phones?