Earlier quoted context omitted.
It's a TUI if it uses text to build those elements. You can be effective and powerful in any kind of interface, Just like you can be ineffective and weak in any kind of interface. People like TUIs because they're cool, and work over SSH.
It's a TUI if it uses text to build those elements. No. All you've done is make a low-resolution GUI.
How about those text games that used ASCII art and you typed in commands like "look" and "go north"?
I would say using text mode is the primary requirement for a TUI. The other requirement being some kind of human-machine connection, IE a User Interface.