It's worth noting that if you wanted to create this kind of real-time app with a Xamarin frontend, you could do it quite easily with ASP.NET on the backend and SignalR.
That's certainly possible for the data part - but a lot harder for UI/code. With the method I'm using, you can actually push code AND UI to the client on the fly. As far as I know, that's a lot more difficult with Xamarin.
Also, the licensing is a lot more flexible than with Xamarin and Qt does provide support for more platforms.
It looks attractive, but at these times, the client application can be easily be auto-updated, that's how all applications work, including those made by Google.
This is not the same thing by a long shot - you cannot force a Google Play update, and that update will take hours or days to trickle down to the users. What we're talking about is that the application updates itself instantly, even WHILE RUNNING. The user needs to nothing, no "update your app" or "newer version available". I can literally add an option in the settings menu or change something in the app and it will immediately be reflected on ALL clients connected without touching the appstore.
Also, the licensing is a lot more flexible than with Xamarin and Qt does provide support for more platforms.