Daily’s React Native library allows developers to build mobile apps compatible with both Android and iOS with one codebase, making it easier for web developers to write code that will get compiled into native mobile code with a smaller learning curve. The Daily Playground demo app uses more of a traditional video call format, allowing participants to turn on and off audio and video as needed. To build this app, developers need to have some React Native knowledge and be familiar with the library's functionality. The tutorial covers how to create a multi-participant video call in React Native using react-native-daily-js, give call participants control of their devices, and render participant media. It also discusses how to iterate over the participant list, controlling local devices in-call, and rendering participant media. The app features an in-call view with a tray that allows users to toggle their camera and microphone, as well as leave the current call.