You can do this few years already with Xamarin. Thousands of developers are doing this today. What this changes is better .Net framework compatibility(less bugs) because Microsoft .Net source code will be reused.
How does this help me from "Desktop app for tracking stars" or "Video game" application developer perspective that I want to build once, publish once and non-technical users will be able to install simply on(Debian, Ubuntu, Fedora, CentOS, NixOS.....) and not depend on distros packagers?
I always wanted something like this to generate terrain for FPS shooting game. So size of this would be lets say 2mx2m and it would be able to create walls on which I could lean to. And of course in combination with Oculus Rift. Of course when I walk in some direction this terrain would have to move in other way so I'm always in middle...
Feels like in future... If cloud provider goes down... All internet will stop working :)