I think a lot of us have forgotten how strange and frightening a blank command line was the first time we encountered it. And how long it took to actually get comfortable with it. Even a windowing system is weird if you're not used to it, and lots of people use those for years and years without ever actually feeling like they're in control of them.

Knowing where the boundaries lie, how to protect oneself from unrecoverable situations and how to get oneself out of bad-but-recoverable ones puts one at ease in front of the keyboard. The absolute n00b (which we all were, once) gets lost navigating directories. The experienced user loses their boot sector, curses, sighs, then fixes the problem. They aren't put off by finding the solution to their problem is to apply a patch to their kernel and compile, and so on. It takes time to reach that kind of ultra-power-user level of competence and confidence, it's hard to teach, but it's enormously useful for letting you put the concerns of basic (ha!) computing in the background and focus on the task at hand (programming, for example).