It depends on what you do, I suppose. If your work doesn't have a large command-line component, using the command line might be disruptive.

A large part of my job involves working with remote Linux servers, so I chose to invest time learning Linux command line tools and vim. Now I'm more productive in a terminal than in a GUI environment. I use common tools that are installed by default on Linux/Unix/OSX, so I can sit down anywhere and do my work, or SSH directly into my machine and have my exact work environment securely and without latency.