It’s more complicated than that (this is coming from one who doesn’t use DB). The most complete technical explanation I’ve found for Scrivener using DB and not others came from KB, Scrivener’s developer, in the thread that JimRac pointed you to. The specific post: iCloud Sync - #14 by KB
And. ask yourself this—would a company not use, without rational reason(s), what is a popular cloud resource? A great amount of thought and work went into this. All evidence points to KB and company as not being fools.Their coding and general reputation is easily found. I don’t expect you to take my word for it—check for yourself. To be clear for anyone who lands here—Dropbox is required for iOS Scriv to/from desktop Scriv cloud syncing; that’s not so for desktop to desktop Scriv syncing. For iOS to/from desktop syncing/transfers, iTunes or similar can be used instead of the cloud.
Good luck.