It was just to change as little as possible and to keep this focused on the exports only.

I believe there is only one place that depends on this['Module'] is here:
https://github.com/kripken/emscripten/blob/master/src/preamble.js#L284

It was in the back of my head that soon I'd do another pr that converted to depending on a local instance of Module as the onload pr did:
https://github.com/inolen/emscripten/blob/b90986c429599d082bf9eae200bb909ea2bec779/src/shell.js#L6
https://github.com/inolen/emscripten/blob/b90986c429599d082bf9eae200bb909ea2bec779/src/preamble.js#L284