I'm using Expo for a home automation app with a local server in the wi-fi home network. It would be great to make the setup automatic by using zeroconf (zero-configuration networking) to discover the server when connected to the same wi-fi. There's a React Native library that implements it (I haven't tried it yet, though): https://github.com/Apercu/react-native-zeroconf
I believe this could be nice for many "IoT-type applications" :)