Basically, you’re creating a webview inside a Win10 app which then calls the website. The main difference between doing this and simply calling the website through a browser is that you are allowed to use the full WinJS API on the website.
You merely need to check for the availability of the WinJS-API like explained here:
Maybe not what you were looking for. I myself am using it to update an business-internal Win10-App easily - I could either update several laptops and desktops every time I change something.
Or I could simply push the change to the webserver. Then again, this is most definitely not something which will work in an offline scenario.
Have you considered writing it as a Chrome App? Apparently you can launch an app that installs and runs sort of independent from the browser and behaves like a native Windows app. They have some API’s that allow you to access different things that the browser can’t.
Google evens has a starter kit that uses Polymer components for material design.
See more about it here: https://developer.chrome.com/apps/about_apps