But if you've already got a captive audience able to run anything .NET 4.0 and above (incl. async/await via Bcl.Async libraries) with the rich experience of WPF, why bother shoehorning a web application as a solution?
Our users are in a manufacturing environment, on a well-known environment. It's practically like developing for a gaming console. And in that light, WPF seems to be a good fit.
We're able to produce a standalone desktop application and a web app using the same code and have it looking/working exactly the same, on different platforms.