Rick Baumhauer points out some intersting things. I, too believe that Apple has put some ridiculous constraints in place for third party file providers and Microsoft is somehow building it's thing around them. I understand they won't point fingers, hence the talk about the new user experience. "This most closely replicates the experience of having Files On-Demand disabled" sounds like they aren't allowed to disable Files on demand via preferences and have to work around it.
If anything this should be brought to Apple's attention. They are stubborn, but eventually listen. iCloud drive could be much better with fine grained control over offline files. Since 3rd parties seem to be tied to how it works, everyone would profit from giving users more control over their data.