HN user
Nice. I think multiple files is more helpful. Expo on a device is pretty easy to get going. I mainly recommended appetize because I think it's a useful feature used in Snack when you click "preview"
I really like the idea of using Repl.it for teaching React Native using your classrooms product. There are 2 things that I think might make it more useful. Integration with https://appetize.io/ and allowing multiple files.
Appetize.io would allow people to use, play, and share this without having install Expo on their device (even though that's already a very low bar). Also, I think after learning some basic React Native concepts, it'd be useful to create multiple React Components in multiple files.