Why is TUI used in stores?

In many big stores/rental/service companys the system they are using for managing customers and looking up products is based on a Text User Interface (TUI). Are there any reason开发者_JAVA技巧 why they choose TUI over GUI or is it just old systems?

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From my experience, it's just old systems. If the old system still works, many companies don't see why they should spend a lot of money only to get the TUI replaced by a GUI.

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Now is 2017 and TUI is still widely used in stores, gas-stations, etc...

I personally find TUI (specially TurboVision based apps) much more eye-appealing then too rich GUI apps. Also, by looking into how users use TUI apps (mostly spend time with numerical keyboards without need for mouse) I get the feeling they are faster in using TUI.