> there is nothing textual about the UIs being shown here.

Well, except:

> a 1:1 representation of the concept within character cells.

TUI is build from text, and living within its constraints and what it's engine (usually the terminal) allows. GUI is build from graphics, and has basically a pixel perfect control of its own. This is a very notable difference, especially at the time when these terms were coined.

> TUIs are generally built for effectiveness and power

No, this is a result of different architectures and their constraints.

> But once you start adding mouse clickable tabs, buttons, checkboxes etc. you

TUI and mouse are predating the GUI (more or less). We had them already 40-50 years ago at the dawn of interfaces. We are now just moving back to them for practical reasons.