I was thinking about this too and found your post. I would imagine the best use of this would be to make it work how react native works in that you would create an amazing engine in c++ that’s lightening fast with fantastic widgets you just can’t do in the browser that transcend normal input types but are easily declared in a markup type abstraction that scaffolds the UI.
You could have it work with any type of thing, even describing character models, sky’s the limit.
The c++ then reads this, parses it out to create its object model, then does its thing.
I think it would be a really awesome experiment.