You can use Linux without a terminal, but life is so much easier to just remember few letters (command) and pressing enter instead remembering 200 places where a setting is. You can also always just do sudo pacman --help.
Strong disagree lol but I understand your logic. I am a visual learner and it is a lot easier for me to understand what the structure and options are in a given program when I have a GUI.
To me the terminal feels like a scalpel. It's a precise instrument, but only you need to know exactly what you're slicing into.