> What is the added value of using it over just Expo?
My answer:
The added value of One is crossplatform compatibility with SSR, and HMR, all using Vite as the single bundler on all platforms.
Nate baked in his vxrn.dev project to get off of Metro and forked Expo Router to do that.
Since Expo Web has a large bundle size, requires NextJS for SSR, Solito for unified filesystem routing, and 2 bundlers: Metro as a bundler on RN plus a separate bundler like Webpack for web.
With One then all of that is integrated. With Zero as the optional data sync engine.