I've seen many people criticizing command-line interfaces as not being usable. They prefer graphical interfaces, and claim they're easier to use. Other people (like me) prefer command-line interfaces. Both are partially correct.
Command-line interfaces are criticized for using cryptic commands, which are hard for a beginner to learn. I agree. I sometimes use graphical tools when command-line tools are available, mostly when I need to do a quick task, and if I've never used the command-line tool. If I know how to use a command-line tool, I will use it instead of a graphical tool that does the same thing.
Graphical tools are easier to use at first, but become more time-consuming than command-line tools, because the mouse is usually used for everything. Moving the mouse takes more time than typing on a keyboard. Imagine how difficult computers would be to use if we had to click on a letter on an on-screen keyboard rather than on a real keyboard.
Roguelikes usually use the command-line, and have many commands that are difficult to remember. Some recent roguelikes, and graphical versions of older roguelikes, allow the use of the mouse. For example, the graphical version of Dungeon Crawl allows both the mouse and the keyboard, allowing beginning players to learn how to play while using the mouse, and then learn the keyboard commands for more speed.