One online feature some users would welcome is integrated collaboration.[1]

Yes, a group of people could invent workarounds such as using Dropbox and copy files to new names such as PetroleumContractVersion1.docx, PetroleumContractVersion2.docx, PetroleumContractVersion3.docx, etc. Other manual methods of sharing could be blasting email attachments back and forth and CC'ing collaborators. Those methods are tedious and error prone.

Another option is to install a SharePoint server and use its document sharing features. That's probably overkill and many folks would think the Sharepoint "cure" is worse than the disease.

Since many folks find GoogleDocs sharing feature to be useful, it seems logical that adding such capabilities to a desktop word processor would help many workflows.

[1]https://www.google.com/search?q=office+2016+collaboration

As other said, if you're a writer, you may not really need real-time instant online collaboration. But for many tasks, sharing, reviewing, editing collaboratively could be gold, especially if the process is lean. The video hinted at that, even though, all video demos are lean and seducing :)

There are a lot of benefits to have an online side when you routinely write documents in groups.