Both. The one doesn't exclude the other. I'm a heavy user of text-to-speech at high rates to digest content easily, but prefer braille when coding or doing some work on a shell/terminal.
You'll see much more braille displays in some European countries because they get subsidized by health insurance or a government entity that provides assistive technology for the workplace. This workstation has a 88 cell braille display, which means it can display 88 braille characters at a time. That unit costs $10k or so, depending on market and EUR/USD rate etc, but to give you an idea of the price tag. I also have a mobile unit with 40 cells, I guess that one is about $6k or so.
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.