Depends... Take for instance a Webbrowser. You could implement one using ncurses, etc. like links, lynx, etc. But for the screen reader this is just a terminal

Depends... Take for instance a Webbrowser. You could implement one using ncurses, etc. like links, lynx, etc. But for the screen reader this is just a terminal window with a bunch of text. A Gui can help the screen reader to know which part to read when and how it releats to other parts of the GUI. Also as a blind person, you live in a world of people that see. You cannot expect every developer to take care and cater to your needs. A GUI that takes care about this automatically for the developer means the dev can just continue doing their thing. While the blind people, can benefit from it as well.