When importing an ODT into Google Docs, it is converted to a format internal to Google Docs. The blog post explains that in WebODF / ownCloud Documents, conversely, no conversion occurs.
For example, WebODF does not support displaying columns yet, but if you have loaded a document with columns, after saving, the columns will still be there.
Adding WebODF into a workflow for collaboratively writing research proposals could be useful. One author adds 'fancy' stuff in e.g. LibreOffice and the other contributors make corrections and additions in a web version of the document.