I think about this sometimes. What stuff can't you do in a Linux GUI that an average person would be able to do in Windows? For the sake the simplicity, lets limit the GUI to Cinnamon, Plasma, or Gnome.
Obviously, there are obscure GUIs out there, but in the main ones, I think just about everything can be done without CLI.
I’m not a Linux wizard but I’m pretty skilled and I love mint. Although, my preference recently changed to Fedora plasma.