Aside from people who also lack hearing, the main issue is are that you are basically tethered to tech if you want to be able to read/write unless you have an a

Aside from people who also lack hearing, the main issue is are that you are basically tethered to tech if you want to be able to read/write unless you have an analog tool like braille. Also, if that number drops below a certain amount, you'll have no one who could read what you wrote and braille stops being useful for anyone to learn due to network effects. Since it's an alphabet and not a language, it's not as big a deal if it dies out, but still a loss.