Xamarin

• Write the model in C#
• Write the views for each OS in their own native way
• Xamarin promises that the new functionality in libraries is added the same day

Telerik Native script

• Write in javascript and call native script's api that then calls the separate OS javascript apis?
• Write the view in html5 and css which is re-usable for all OSs as they now all support html5 and css front ends?
• Telerik simply states... and I paraphrase 'it does not have this problem'

If the above is so, how is Telerik any better than Xamarin as it states on its website:

  
"When using NativeScript the new additions to the native platform are
  available immediately. This is not the case in neither Xamarin or
  Appcelerator, where there are technical limitations and wrappers needs
  to be created when new native platform features are added."

I am confused at how Telerik is being penned as being better than Xamarin when Xamarin comes with strong type language without using TypeScript's slightly loose thing going on. And also that Xamarin does in fact sit in exactly the same boat as Xamarin apart form the view part... which is actually supposed to be a benefit?

Question:
- What's the difference between them apart from the two I have denoted?
- Why would Telerik claim such a thing?