From what I can tell, it means you no longer need to write/maintain gulp scripts and you don't have a build step during development
My understanding is that this tool removes that entire class of annoyances, and gives a no-hassle live-reload ES6-enabled environment on top.
https://gist.github.com/substack/68f8d502be42d5cd4942
Importantly, overloading require like this:
var collections = require('npm:lodash-node/modern/collections');
var $ = require('github:components/jquery');
... means that you can't publish this module to npm and have the require statements work as expected.So you end up with the same workflow as shown in this video; but most likely faster for many modules (browser requests 1 JS file rather than potentially hundreds) and also more realistic for production (aside from minification, the dev environment is the exact same as the production environment).
p.s. For prototyping like in the vid, you can use tools like beefy or wzrd to avoid setting up any browserify build step. :)