Yes this is not production ready, and to be clear that's essentially the mobile app deployed as a web app. So the mobile/desktop apps are definitely not going away, but it means that any new mobile version we create, we can deploy it for the web too (provided this PoC works out well and it looks like it does). This is convenient for people who cannot install apps, for example on lock down devices, or simply for those who don't want to install any app. Then it runs with only the permissions of the browser.
I wonder how hard it would be to convert some of the existing apps to use Lemmy. I guess the federated aspect makes it more complex and will require more development than just switching the API, but the UI could stay similar.
I'm actually amazed how well it works and how many plugins are compatible. Henry did a great job on this feature!