I like a TUI when I always want an app to run side by side with a CLI. It’s easier to do split windows in a terminal or tmux/zellij panes than to script two separate app windows to stay locked together as a pair. Although, I’d welcome advice as to how to do it better.

I also find TUIs are easier to program for the same reason they’re limited. Fewer human interface aspects in play and it’s not offensive to use the same UI across OSes. (There are still under-the-hood differences across OSes, e.g. efficient file event watching.)