To expand on your first statement, it's helpful to have a project you are interested in using once its operational. Learning something for its own sake isn't very motivating. But if learning the skill allows me to do something I am truly interested in, then the learning is just one of the steps in the process, and you have a much more directed approach.

It's the difference between "figure out how to use websockets" vs "build a temperature controller for a smoker that is accessible from a webpage, using websockets".