Sure, if you need to move a bunch of files whose names don't match any particular pattern, then using a GUI tends to be more efficient. Suppose you have a directory with a hundred documents in it, and you want to categorize them into subdirectories. With a shell, you'll probably actually need to have two terminals open, one to keep the full list of files available, and one to type commands. You'll mv file1, file3, file4, file7, etc using tab-autocomplete, but it's still going to take a bit of typing and a bit of time. With a GUI, you look at the full directory contents in the file manager, control-select each file you want to move, and then drag them into place. If there are a lot of files, and they don't have filenames that match shell patterns, then a GUI can be faster.

You can copy and paste, but not cut and paste. Moving with the mouse isn't so bad though -- you can select the files and start dragging them on top of folders. If you hover over a folder for a few seconds, it will open, and then you can hover over another folder to open it, etc., until you get to the place you want to be.