Microsoft is interestingly marketing the feature towards interviewers who need to test candidate’s engineering and coding abilities. However, the feature could be used in so many other ways, including being able to write a simple program live with your colleague or friend. The feature also isn’t available on Skype desktop as of yet, and users will only be able to use it through Skype on the web if they are on Google Chrome or Microsoft Edge.
Skype only recently started testing a new, modern desktop app for Windows and Mac, which is built on web technologies such as Electron. So the real-time coding editor will likely get added to the modern desktop app in the near-future.
You can checkout Interviews on Skype here.