Just getting started with React-Native (for the non-CRNA/Expo case) and it's not clear to me after reading the react-native docs or Understanding the CLI when it's appropriate to run react-native start
react-native start --help simply says starts the webserver. Running react-native run-ios also starts the same server except it also actually runs it in the simulator.
Question: When is it appropriate to run react-native start vs. just running the simulators directly (i.e. react-native run-ios)?