Just from my own experience, CLIs are important to have with regard to automation, scripting, bulk updates, and other things that can easily be pre-staged and pasted out of a notepad file, etc. In that respect, it's quite valuable to have CLI capabilities as a shop scales over time, introduces more complexity, or needs the general granularity that a CLI might provide.
When those things aren't necessary every day, however, a well-crafted GUI is the perfect tool in the box for look-n-see/general health/general info acquisition, screengrabs for courtesy or formal reporting, or just the simplicity of the single-tool (i.e. browser) functionality.