iCloud Sync

There’s nothing wrong with your method if you’re keeping track of your versions and are unpacking the archive outside of iCloud Drive if your intention is to not store a live project there. The following article explains the method more comprehensively in its Alternate Method section, and describes best practices for using desktop Scrivener with cloud syncing.
scrivener.tenderapp.com/help/kb … c-services

A good discussion was had here about iCloud Drive and desktop Scrivener:

I’ve been experimenting with placing both archived backups and live projects in iCloud Drive, and the experience has been positive. Again, I’m talking about syncing between Macs here.

Dropbox is required for cloud syncing with iOS Scrivener. Two sections of an L&L article explain why that is (the full article is a comprehensive iOS syncing paper).
scrivener.tenderapp.com/help/kb … automatic-
scrivener.tenderapp.com/help/kb … solutions-

Part of a writer’s job is to prepare for the inevitable failure of software or hardware. A solid backup plan is mandatory no matter the sync method.