WHY DOES IT PAY OFF LEARNING THIS?
Graphical user interfaces (GUIs) are helpful for many tasks, but they are not good for all tasks.
Computers were supposed to free us from manual labor, but how many times have you performed some task you felt sure the computer should be able to do? You ended up doing the work by tediously working the mouse. Pointing and clicking, pointing and clicking.
THE CONSOLE IS HERE TO STAY
Another good reason is: console programs don't change much over time, and last very long. GUI programs change much overtime and often need re-training (Microsoft Word undergoes a metamorphosis almost every release). So basically, eventhough you have a Microsoft Word-certificate, you still need to learn a totally different GUI application every time. At some point, computerusers start realize this. They decide to not participate in this never-ending-cycle, and start learning some console-commands. The commands can achieve similar results (sometimes even faster). Luckily there are operating systems which are based around the console (GNU Linux/Solaris/Windows 7 with its powershell, and even Windows 3.1). Lots of these operating systems have the advantage that the console-commands are maintained, upgraded and used on a daily basis by many users. The result is: you learn something once, and use it for many many years.
DONT TAKE THE MOUSE FOR GRANTED
Its time to grow up, and decide when to use the mouse or the keyboard.
If not, thats fine, we'll catch you later here as soon as you realize you have been warned.
BASH, ZSH, DOS ETC
There are many shelltypes, so why not check out some of them here and start learning today!