It's also usually inherently composable, since you can pipe and redirect and everything speaks a common language (plaintext, for better and worse). If you just naively implement a cli tool, you usually end up with something that can reasonably be chained or redirect into/out of or combined with xargs etc.
It's like if every single GUI program included easy recording of macros and had built-in tools for munging of data to input fields and from text information.
There is a really solid place for GUI tools though and that's where the task is inherently visual (nontrivial tabular data, anything with images or video, etc) or where discovering your features and guiding people through a workflow is more important than it playing a part in a text processing pipeline.
Honestly, file managers are probably a good example of something that really ought to be a GUI and I've always considered it a bit zealous of people to want a TUI for it. Just look at this thread alone - people accidentally deleting files because navigation and actions are so undiscoverable that if you don't just blindly copy vim, even highly technical people will have no idea how to use your tool.