Learn How OneDrive Sync Works With Office 2016

A) I was under the impression that OneDrive already sync'ed only the parts of a file that had changed, because... efficiency. Does OneDrive (without the Office 2016 integration) actually copy entire files for every little update or change to a file? How often would it be doing this? In the example you describe, with the large video in a PowerPoint file, would OneDrive really upload the entire file every five minutes or so, the whole time you were editing that file if one had this option turned off or if one were using an older version of PowerPoint?

B) Does the Office 2016 program need to be open, with that file open, in order to make these piecemeal synchronizations? Or does enabling this option allow these kinds of piecemeal synchronizations any time after said file has been initially opened by a Office 2016 program?

C) In order to initiate this feature, do I need to open said file from the OneDrive web interface, or do I  open it from the OneDrive folder on my hard drive? Or, Is there some way I can indicate, as I am opening or saving a file, regardless of where it is located, that said file should be added to the list of files that are synchronized via OneDrive? None of the documentation is clear on this point. It just says, "Use Office 2016 to sync Office files that I open," but does not say from where. I know, one could assume they mean "from OneDrive" but one never knows. Plus, this leaves seems to leave the user guessing as to which files will be opened in this manner and which won't. 

Yes, I know I'm being a little pedantic here. But that is what good technical writing is all about. 

Reference:

https://support.office.com/en-us/article/use-office-2016-to-sync-office-files-that-i-open-8a409b0c-ebe1-4bfa-a08e-998389a9d823