I personally like making (and using) TUIs because:

- They encourage developing simpler, information-dense, and keyboard-driven interfaces, which I tend to prefer in general.

- I find them more fun to write, and less aggravating to maintain and debug, than interfaces built with GUI toolkits.

- Most software I write for personal use is going to be run in both a Linux and Mac OS environment (and a lot of the time on a headless server to boot), and a TUI often has less fuss than other options (at least, IME).

- I think monospaced text in a terminal just looks cool.

But you can't really do information dense when you are limited to a fixed grid of monospaced character glyphs. Variable width fonts are much more information dense for example.