Slack in the Windows Store is packaged by that. It packages the Win32 executable, so it only runs on Desktop environments.
If your codebase is adaptable enough, you can often run directly on the Windows 10 Native HTML+JS stack and cross-compile to that, either directly or maybe through Cordova if you want mobile platform reach.
(I'm wishing there were more convergence between the Electron and Cordova stacks, but writing portable code that mostly runs on both isn't terribly difficult. Every now and then it would be great to have a Cordova plugin in Electron or vice versa.)
There's also a 'native' HTML+JS stack for UWP/Win10.
But why not?
The singular issue with electron is how fucking huge the simplest of apps have to be. I see desktop HTML/JS as a RUNTIME being a very near-future standard.
I'm sure electron has thought about it. It couldn't possibly be any bigger of a hassle than the java runtime.
I don't think it is "sexy" to most developers right now because there are still a lot of developers that still cling to ancient "native" control toolkits, ancient ideas that web platform is already the main UI platform for the majority of user these days, and for whatever reasons dislike HTML and JS for application development. You see a lot of the complaints here on HN every time Electron or Cordova are brought up.
I'm sure Microsoft knows they don't get a lot of enthusiasm from a lot of developers for the native Windows 10 web stack, so I'm not surprised they underplay it at conferences. Those of us that do care know we can follow the Edge team blogs and know that UWP API enhancements benefit all three main stacks.