For running a mobile-type app on a desktop environment, I’d usually say that a website would be a better choice (and the JB team is currently looking into Compose for web, too).
So IMO that leaves native desktop as more useful for complex apps that need more screen real estate than a mobile app and the ability to do more local data processing than you can with a website or that would be prohibitively expensive to run in the cloud (file IO, batch processing, image transformations, etc.)