For our startup tagtog.net this is useful because we like having all centralized into our docker folder and so not miss important documents in other services.
It should also be noted that Dropbox already had Office Online support for a while, which allows one to edit Office files that are stored in Dropbox in Office Online. This integration stores the actual Word/Excel/PowerPoint documents on Dropbox, so after syncing you have these files locally as well.
One of the huge benefits of Dropbox was that everything ends up as a normal file on your hard disk, that you can archive/backup. Unfortunately, that is not really true anymore, since Dropbox Paper docs are not saved to Dropbox.
You can save a copy of a Google Docs document on your drive in a Microsoft Office format, but that goes in one direction.