How can it not be true though? Terminal shines when you chain together more than one operation.
Imagine doing this in a GUI: list the files in a large directory, ignore the ones with underscores in them, find the biggest file, read the last 1000 lines from it and count the number of lines containing a particular string.
Thats a couple of pretty straightforward commands in a terminal, could take 30s for an experienced terminal user. Or the same task could take many minutes of manual effort stuffing round with multiple GUI applications.
I’m certain that I do tasks like that (ad hoc ones, not worth writing dedicated software for) tens of times in a typical work day. And I have no idea how GUI users can be even remotely productive.