I write shell scripts all the time. I have probably written hundreds of shell scripts this year.
If you think it was to avoid using a gui, I would have to say that's not really it.
It's more to do something (automate stuff) rather than not do something.
I learned about zenity but chose yad instead - it has the same interface + a few more bells and whistles.
What it's good for is launching something you'll do on your primary display, that has a lot of options that you might change individually.
probably also good for a phone. I learned about yad reading this article:
https://wp.puri.sm/posts/easy-librem-5-app-development-flash...