Your breakdown is pretty spot-on: just like with regular native development tools, native code cannot be “hot updated”, no.
For JS/“dumb assets”, we are currently in the planning stages of figuring out how that will work in practice, as it needs to be engineered in a way that fits with the UX way of working. Most likely it’ll involve some sort of backend service that you can use to manage and push updates from, but it’s too early to either promise or give specs on.
Rest assured, it’s something we’re already interested in and working on.
Any update on this feature. Its a killer feature. Microsoft code push already supports Reactnative and Cordova apps. Meteor can also update cordova apps.