This is confusing indeed. Don't mind optimising Photos, iTunes and other stuff, however, Desktop & Documents better be fully offline.
Could someone confirm whether it is possible to have Desktop & Documents synced to iCloud while also having them FULLY downloaded to the Mac at all times (no optimisations going on at all)?
During one of the early Public Betas I had iCloud Drive>Desktops and Documents enabled (and with appropriate backups made first of course in case of disaster) and confirmed local copies were made simply by turning wifi off on my iMac and opening the shadow copies of some of those documents still showing in Finder>iCloud. Of those spot-checked, all were intact with no data missing.
I then repeated the check after performing a complete shutdown on my iMac while it was offline and spot checked additional documents after I logged back in with the same results (all the data was intact.) Finally, I added data to one of the documents while in offline mode and after re-activating wifi that new data was added to the version stored in iCloud within a few minutes.
I'm still a bit torn about entrusting my documents to the cloud so have disabled the feature for that reason as well as the process itself still being somewhat in a beta state but I hope this helps others considering dipping a toe into these waters.
regards,
BD