Really simple answer: Repeatability. I am not saying it is the only one right blessed answer, but if you really want to know why people haven't moved to pure GUI interfaces, imagine describing to someone how to add a new directory to their path.

  fleet $HOME/.config/fish.config
  # ADD this line somewhere
  set -x PATH /opt/git/bin $PATH

Or: 1. Either hit WINDOWS-E and right click on This PC and select properties (it might be called something other than This PC if someone renamed it) or either press WINDOWS key or click Start or click the Windows icon (if you don't see them try mousing into a corner of your screen (typically bottom left) until they and the rest of the bar un-autohide) look for and click a gear symbol (should expand to say Settings if you hover), click System, on the left and the bottom you should see About. 2. Click the text Advanced system settings (on the right), look for a new window with a set of tabs, you want Advanced. Click the button Environment Variables. 3. In the top columnar box EITHER find a variable named Path, highlight and click button Edit, in a new window click button New, type '/opt/bin/git' in a text field that has appeared at the bottom list items, click OK OR click the button New, in a new window enter Path for Variable name and /opt/git/bin for Variable value, click OK (you shouldn't need to Browse Directory or Browse File). 4. Click OK button, click OK button, close Settings window.