Why does the Matlab .NET interface to Microsoft Word use a reserved internal class?

In the Matlab documentation there is an example of working with Microsoft Word Documents using .NET. In this example, the application is instantiated with the class Microsoft.Office.Interop.Word.ApplicationClass, which, according to MSDN documentation, is reserved for internal use. MSDN documentation instead suggests using the interface class Microsoft.Office.Interop.Word.Application, but this does not work, as the constructor appears to require a COM object (using methodsview), which is not mentioned in the MSDN documentation.

So, why does this happen, and why does the Matlab .NET interface to Microsoft Word use the reserved internal class?