Code is more expressive than configuration
Configuration:
Your ability to customize [...] is limited to the extent the developers have correctly anticipated your needs.
Code
Your ability to customize [...] is limited to the extent you can describe what you want in code
Learning to code gives you transferrable knowledge across projects and tools.
Your potential mastery of [an] RSS plugin data schema won’t help you in a different blog tool, or even using a different [...] plugin. In contrast, learning an interchange format like RSS or (here) JSON Feed is knowledge you can apply elsewhere, as are the data manipulation techniques
(This is a good series from Jan Miksovsky where he articulates all the reasons why I love Web Origami as a tool for generating websites.)