Evidently nobody has told Tim Cook that Mac Office 2016 is a subset of Windows Office 2016; also see Office 2016 For Mac Is Unstable On El Capitan, Be Careful If You Upgrade (Thurrott)
"“If you think back in time, Apple and IBM were foes,” Cook said. “Apple and Microsoft still compete, but we can partner on more things than we compete on. And that’s what customers want. [Apple users] love Office, and they want it to work on Mac better than it works on Windows, and it should.”Tim Cook on Apple and Microsoft partnership: 'It's what customers want' | Macworld
During Apple’s last event on September 9, Microsoft presented new Office features for the just-announced iPad Pro.
“I’m not a believer of holding grudges,” Cook continued. “Having as many friends as you can, you can deliver much better solutions, and that's what the enterprise wants us to do. Companies want to partner with other companies that are part of an ecosystem, not on an island by themselves. The island days are gone.”"