I don’t get Webpack

I keep seeing mention of Webpack in various JavaScript discussions, but I just don’t get it. I don’t see where it fits in, where it starts and ends or what it really wants to be.

Most Webpack introductions I’ve read start by comparing it to Browserify, then mention how it’s rolls in Require.js style AMD modules  – as if that were a good thing. If Webpack were just a better Browserify, that’d be great, because Browserify is pretty great already.

But then things get weird. Webpack can (with a loader) process Sass files? It gathers image assets? What? It watches files too? But I’ve already got Gulp* doing all that and the workflow is really good. Can Webpack work with Gulp? Does it replace Gulp? Why so much redundancy?

Finally Webpack throws in a static web server. Well now just stop right there. BrowserSync is ten kinds of awesome and much more than just live-reloading pages; device synchronization, mirrored input, bandwidth throttling and DOM outlining are going to have to be pried away from me. 

* I know Gulp is supposed to be gulp, but proper nouns and English.