$ google youtube post --category Education killer_robots.avi
as compared to uploading a video after several clicks, and waiting for server round trips page after page. Since it's already known that the command line will be used by the power users only, it makes the life of the programmer easier (instead of assuming the end-user to be infinitely stupid). Consider this second example
$ google calendar add "Lunch with Jason tomorrow at noon"
Did you see that? Did you see? "Tomorrow at noon!" How beautiful is that! The system will itself figure out what you mean by "tomorrow" and "noon." While it's possible to give the same power to graphical users (and I am sure that Google Calendar does), you can't expect all users to understand how this would work, or manage it if it doesn't have the desired affect. Such behavior is the ultimate power tip a user can get with reference to Personal Information Management tools.
But when is a click more powerful? Perhaps only one thing beats words: a picture! And it's only there, clicks make sense. But did I tell you that I love words?