> No giant gaps between elements or wasted pixels. No fads which do silly things like hide scrollbars or other interactive elements

I call bullshit on this.

Using fixed character cell grid for UI absolutely wastes ton of space. First of all just basic text takes more space in fixed-width than variable width. But the biggest offender is any layout or ui elements that would not need whole cell. Even basic 1px horizontal line takes 10px of height or whatever. Places where 1 or 2 px padding could do will use full cell instead.

And then there is of course the space waste from forcing all text to be same size. For tons of applications the UI elements could do with smaller font than content, but none of that is possible with TUI.

I find your example of hiding scrollbars hilarious, considering that TUIs are in general far worse offenders in that area specifically. For example none of the examples for Rich here show scrollbars..

I do also believe that in terms of performance TUIs leave lot on the table, because they are forced to go through all sort of weird legacy layers. Pushing pixels on screen and receiving key events directly almost certainly should be faster/more efficient than going through tty layer and terminal emulation.