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.)

There are some applications/systems for which certifying bodies forbid the use of web management because of vulnerabilities in both the protocols and the clients and servers. For example, in my daily, several national cyber organizations (NSA, CSE, GCHQ, etc.) have such direction. That's why our main product line is managed using a TUI accessed at the local console or over SSH (with very, very carefully curated SELinux MAC, among other things).

Having said that....

If one is willing to build one's own HTTP server with integrated MAC, etc., and is able to demonstrate mitigations against known vulnerabilities, one may be able to get the certifying bodies on board. Time will tell.

Yes, this is very niche, but TUIs are in general niche.

In practice, TUIs tend to have good keybindings, & are readily available right in the place where you're running the command (especially for quick tasks).

TUIs work well over ssh. Pretty much everything else is a pain in the ass in some capacity, especially when the ssh client is a smartphone.

Gemini made a lovely TUI for my C# project, but afterwards it said it could just spin up a Kestrel web server inside the app instead which would be a much better solution for managing it, which was fair. (I have a line in my Agents to warn me when I specify a way of building something and it's not the ideal solution)

TUIs are much easier to run in a container, for one thing. Though, I guess a terminal-based web browser would work for some web apps.

Having a tui file picker in the pipeline can be a powerful technique. Sometimes it just makes sense to have an interface that is slightly more interactive than pre-selecting all the files makes the flow smoother. Being able to put that into a script/alias/whatever is nice.

Other CLI things benefit from this "have a minimal ui interface in the workflow for the one step where it makes sense".

I just added a TUI built on Charm for my custom agent. I primarily use it for two things.

1. Navigating all my chat sessions and doing admin work. It's super fast to push a single key to go in and see what it was about before deleting it.

2. Testing out features and code changes without the web UI / vs code extension complexity.

3. Places where I cannot connect VS Code. I still want to chat and see diffs, a TUI is much easier than a CLI for this.

It also has a CLI, basically three interfaces (CLI, TUI, GUI (vscode/webapp)) to the core features of my personal swiss army knife (https://github.com/hofstadter-io/hof)