If you are in the US, pick a slow day and chat to the customer service people at Lowes or Costco. Both stores use TUI interfaces for their instore service apps, and boy are they fast with them. They reserve GUI things for the self service point of sale systems and keep the TUI for cases where speed matters. I suspect that these apps might once have been mainframe hosted (in other words, screen-oriented, with the PC terminal doing local processing and not sending the request to the server until the user hits Send) but of course those days are long gone and I imagine that at worst they are running on a TN3270 emulator and more likely they just expose a remote app in a browser or RDP session.
Some things I observe from watching these apps is that navigation clues are always present, keymappings are static from screen to screen (F1 is always help, say), and the UI is such that the user is always in control of the application state.
Some things I observe from watching these apps is that navigation clues are always present, keymappings are static from screen to screen (F1 is always help, say), and the UI is such that the user is always in control of the application state.