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.