I’m fairly certain this terminology has been around since at least the early aughts.
https://en.wikipedia.org/w/index.php?title=Text-based_user_i...
Norton Commander (or Midnight Commander) is probably the quintessential example of a powerful TUI; it can do things that would be quite hard to replicate as easily in a CLI.
https://books.google.com/ngrams/graph?content=TUI&year_start...
Basically it was never used, then it was heavily used, and then never used, and then in the early 00s it took off again.
That'd explain why you used it, I never did, and now young kids are.
It's not a term I recall hearing at all when I started using computers in the mid-'80s - all that mattered back then was "shiny new GUI, or the clunky old thing?" I really thought it was a retroneologism when I first heard it, maybe twenty years ago.