Why do people want braille displays? Sound is a faster, denser, and cheaper information exchange medium and our brains are pattern matching machines. I can easi

Why do people want braille displays? Sound is a faster, denser, and cheaper information exchange medium and our brains are pattern matching machines. I can easily imagine a screen output -> earphones technology that can provide the use of a screen. Wait, why confine this to screens? There was a deaf guy in Popular Science years ago who wired the output of a microphone to his visual cortex. He was able to see the sounds, not interfering with his normal vision. Why is there no such product to wire a camera to the brain to enable vision in the blind?