Calculator is a great project for developers starting with UWP. However, it is implemented in C++ with managed extensions which I would consider rather a niche language with a niche features in a niche area of UI development. It is a niche within a niche within a niche.

I know C++ but would never consider this language for UI development. This ship has sailed around year 2000. On the other hand if Microsoft would pay me a huge salary to develop UI apps in C++ I would seriously consider it. Then I would say no.

Having calculator project in C# would make this project accessible to a much wider audience and maybe would help adoption of UWP somewhat.

Please consider converting this project to C#. Future generations would thank you for it.