Computer software (and hardware) companies make their money by selling you new versions of their products. And to make you want (have) to buy these updates, they like to change things around so it seems like you're getting value for your money. Microsoft loves to change their user interfaces, especially on programs such as Excel and the rest of their "Office" applications.
So what is a tutor/teacher to do? Teach the specific version that the student has? But what if it is a group or classroom setting? Teach only the most current version? Should the tutor be forced to purchase every version of an application that they teach? Hey, I'm still very happy with the functionality of much earlier versions of MS Office - and having used/taught these programs for over 25 years, trust me when I tell you that I've had to learn a lot of different GUIs over time.
That's why I like to teach concepts and functionality, and let the student dig in on "homework" assignments with the GUI of their choice to learn what keys to press (menus to mouse). This allows the student to learn with their system, and be prepared when the next marketing guru decides to release a new version and yet again change the user interface. Hey, I'm not really complaining, it sure does help in job security when you can teach "refresher" courses on the new version! lol