@Sam91 This is a common misassumption with Chromebooks.

1) Yes you can do document editing on a Chromebook offline - you do need to download the Chrome addon to make this happen.
2) There are also many other things you can do offline.
3) Not everything on a Chromebook requires being connected to the internet. I'd often watch movies stored on mine for example.

Once Android apps for ChromeOS comes in early next year it'll also take care of other things such as Microsoft Office where as from next year you'll be able to run the Android version of Microsoft Office on a Chromebook.