Maybe I'm wrong, but it seems like the advantage here is that as people loses their sight (slowly or quickly) they would quickly be able to pick up a tactile font with little to no additional training. Normal sighted people would also be able to read things in the dark (safety factor for things like power outages). Percent of people with blindness and vision impairment drastically increase by age so I think it is safe to say that most blind people aren't born blind.