It's complex but it's worth learning. You can do a lot with it; transpiling, bundling, source maps, css modules, autoprefixing, concatenation, minification, etc. Along with npm scripts and a little shell scripting you can pretty much do whatever your project needs, including auto Dev deploy, ci, one touch versioned stage/prod deploys with rollback etc. And it seems to be the common base people are building the best plugins for these days. It's far less verbose than grunt or gulp, and plugins are not needed for every little thing as a wrapper. But when you need plugins, there is a great system for them, and a ton of community plugins available.