Even if the app used the bash script as the backend, the UI would require dependencies (aka tray icon)

You dont need a UI for things like this.

Maybe you don't, but the author did/wanted one. It's a good thing your exact needs don't control how other people use their computer.

Its also reckless that you install 200 deps that can in theory read/write and do anything to your OS. How do i know this thing is not listening to my keyboard? Etc...

A uI tray icon is usually a few os calls away. I does not require 200 deps.