The idea is to have a single immutable data store. Immutability gives you, among other things, easier time debugging and reasoning. Having a single, global data

The idea is to have a single immutable data store. Immutability gives you, among other things, easier time debugging and reasoning. Having a single, global data store means that the entire state of your application can be managed centrally. There are no seemingly unimportant variables hiding anywhere that would drive your app, it's all in one place.