This is a feature, not a bug.
For me, browsing 20 pages of --help or man is a discoverability nightmare. I don't want to wade through arcane option after arcane argument.
The GUI gives me a well-organized top-level understanding of the program: organized menus, and organized panes (panels/palettes/tabs/etc.). Then I can drill deeper into dialog boxes and tool settings as needed.
It's far more efficient to quickly browse a GUI to figure out the lay of the land, than it is to wade through what is essentially the reference manual of a CLI tool.
Reference manuals are the opposite of discoverability.