The 12% figure refers to legally blind children, the majority (90%) of whom are partially sighted.
For someone who is able to read text at close distances with significant optical assistance, it is far more beneficial for them to learn a written language than to learn braille characters. Until recently, many legally blind US children (and their parents) had the choice to either learn braille or written English. Those who learned braille ended up severely disadvantaged because of the utter lack of braille information produced in our society, and the difficulty of using any screen-based technology.
For someone who is able to read text at close distances with significant optical assistance, it is far more beneficial for them to learn a written language than to learn braille characters. Until recently, many legally blind US children (and their parents) had the choice to either learn braille or written English. Those who learned braille ended up severely disadvantaged because of the utter lack of braille information produced in our society, and the difficulty of using any screen-based technology.