Google Docs is a reasonable comparison, but, a couple of things:

First, we do discrete versions/snapshots, so you can revert back to a particular version in time (along with seeing the associated conversation). Thing something like Github but for non developers.

Second, we support literally any file type. We integrated with Microsoft Office Online to support co-editing live in browser (which is the "like Google docs" portion), but we also support literally any other file type for conversation and activity feed: Photoshop, InDesign, PDF, etc. For many of these files types we also provide live previews and so on.

so how does it compare to just Office.com/WordOnline/OneDrive/SharePoint

it has full versioncontrol for all filetypes and provides your coediting in the browser. Why would I use you as my version control over sharepoint, the thing built into Word Online?