why would a gui app be more readable for reading text? The only inate difference I can think of is the ability to vary fonts and rendering based on what you are rendering more.

And that can be a nice improvement to e. g show your code at a normal size but pop a tooltip up with smaller text, or have the linter/errors tab be a smaller font.

But that's a difference and not necessarily an improvement, because having a consistent font and fixed width text can make things more predictable and faster to interact with as you don't have to scan around as much.