The GUI was developed by Xerox PARK in 1973. Since then not much changed, we still use window, icon, menu, pointing device (also referred as WIMP). We have lot of fancy, new features like desktop search, more colorful icons an we like, but still not much changed.
As useful as this approach might be is doesn’t scale. Ever tried to find a bookmark out of a list of thousands? Trying to find something in such a huge menu is nearly impossible. Probably it’s easier to just google for it. The point is that with 5 letters you can select from millions of possible combinations. These 5 letters you probably type in under a second.
“Wait!’ you might say “Are you saying the command line is superior to a graphical interface?”. Well, I am not. Most people fear the command line because they don’t exactly know how to do what they want to do. There is no list of options to select from (or it would be too long). Another downside of the command line are cryptic commands like “tar -xzf”. The learning curve is step. Again take a look at google suggest to see how to improve the situation. It’s a really helpful feature to find what you are searching for quicker.
Now just imagine your could click on your file press a key and then type “tar”. The command is smart enough to realize the file you clicked is not yet packed, so it’s packing it, maybe first it suggests the name of the archive to be “some_filename.tar” which you accept by pressing enter. If you click on an tar archive, it would “know” you want to unpack it. Sounds simple? Well, it is. Still not convinced? Then try it yourself with Enso (Windows), Quicksilver (Mac), Ubiquity (Firefox)