Not really. I'm a WPF developer by trade and have written several Windows Phone and Store apps. Having done this I've had to pretty much re-write the front end of the app to take into account different form-factor layouts.
Different form-factor layouts hare not fun to write in XAML. If you're looking to spend all your time writing different screens for different size views, go with Xamarin. if you want to write one app and then apply a bit of styling to manage different layout sizes, you'll go down the HTML 5 path and use something like AngularJS.They're embarrassingly easy to write in HTML.
Adding in employability: I know of nobody that writes all their mobile apps in C# or Xamarin. Most business doing LOB apps have gone down HTML 5 (no installs, no having to learn a device specific language). If you're writing apps for external customers your situation may be entirely different, but at that point I'd expect you to have experts who will write the app in app-specific languages where you have to or give you a Cordova app.
So, I'm going to say it again. Pointless.