Why do we need Skype et al on Chromebook - should Google do everything for us?

My last blog post concerned how to install Skype and other applications on a Chromebook. The task is straight-forward and I believe the blog post is informative - but it generated some controversy. The controversy wasn't over the methodology, but why would I want to do that in the first place? Aren't Hangout's sufficient to replace Skype?

Installing Skype, photo/video editing, word processors, and more on a Chromebook

Chromebooks offer respite from antivirus software hassles, system maintenance hassles, and more. The idea is that with the Chrome web browser as the only user interface, people can compute in safety. But what about the whole slew of existing software that runs outside web browsers - Skype being just one example. What about video or audio editing? What about traditional word processors or spreadsheet applications? None of those run inside a web browser. Yet.