The title seems irrelevant.

With the exception of frameworks like Ocsigen/Eliom[0] and Dart[1] (Eliom being the closest thing to what the presentation hints about), I've never seen any production web apps that have been compiled from languages like Ruby, Python or C (I don't consider desktop applications like Banana Bread a web app). Lack of frameworks and best practices for DOM manipulation seem to be roadblocks.

The presentation didn't list any examples of web apps written in other languages, so I'm forced to conclude that if I have a big web app, compiling it is not the most sensible option.

[0] http://ocsigen.org/overview/eliomapplications [1] http://www.dartlang.org