On learning tool
There is a fairly important point that is missed by this article. You do not need build tools to write JavaScript and depending on which tools you use there are significant drawbacks to using any them.
Before you dive into the world of build tools and process management I urge you to write unminified, ES5 (aka the JavaScript that runs without transpilation today) until it hurts.
Write unminified JavaScript and watch your page load times.
Write ES5 and time how long it takes you to complete projects of a given size.
Write reactjs code but use the JSXTransformer. Watch page performance. Watch how many times you reload the page in a given sitting.
It's really only when you find yourself with a problem that you can quantify that these tools start to make sense.
Discover for yourself why these tools exist or you'll waste a ton of time learning the newest thing and in the end not have gained much at all.