Yeah, sorry I wasn't clear why. The first is that React is pretty large so it slows down the watch/build cycle enough that there is a lag and second is that in production React can be loaded via a cdn. Since everything is bundled into one file with Browserify its better for the end user download speed if you pull 3rd party libs out.

I also didn't give the main reason for using the NODE_PATH method. Browserify doesn't resolve duplicate relative paths so if you have a structure like this:

    /src
      main.js
      components/a.js
      components/foo/b.js
      components/foo/c.js

and a.js requires c.js via relative paths:

    require('./foo/c.js')

and b.js also requires c.js via

    require('./c.js')

then c.js is included twice in your bundled code since Browserify uses the pure string path as the key. If instead you put /src in your NODE_PATH you can do this in a.js:

    require('components/foo/c.js')

and this in b.js

    require('components/foo/c.js')

and c.js will only be bundled once since it has the same path.

Because writing the require statement in every file is annoying, probably. I do something similar with jQuery - I require it in my bootstrap file, then do

    window.$ = jQuery

Global variables are a bad thing until they're a really convenient thing.