Yes. This LONG “short”cut actually works. Try it. In fact, just press Alt and choose the highlighted buttons in the Ribbon. All of them work. Just press and release Alt and then press buttons one by one. DON’T try some Yoga poses with your fingers 
With Outlook 2016, This shortcut is now Alt N AF B. This is required because it offers to attach files from local PC as well as web locations (OneDrive). It also shows recently inserted attachments.
