The forest is shrinking the time and distance between code we care about and visualizing the results. WASM and an in-browser environment is the tree. Even for experienced devs it's not always readily available to have a web server, PHP, a database, and WordPress running where you can quickly make a change and test it out or demonstrate it to others.
This makes it possible to ship a WordPress site as a demo site (with pre-filled content and structure) where anyone can show off their WordPress plugin or theme without needing to have a backend or worrying about securing it.
Aside from that - this thing uses SQLite for a specific reason - the browser can't connect directly to a remote DB, so any content you create in this instance is visible to precisely no one else. As such, it's certainly not an answer to actual publishing use cases either.