Windows 10, hamburger menus and UI design

Originally posted at https://vid.me/RQsM this video is from someone who "designed the new version of Office for Windows Phone" as found in a recent Reddit AMA. In it, he explains why Microsoft has chosen to go with a top Nav bar and hamburger menu. More info: http://www.windowscentral.com/why-microsoft-hamburger-menus-windows-10-phone