Add reason to use Redux

README.md

@@ -170,7 +170,7 @@ While Redux does not necessarily have to be used with React, it is highly recomm
 
 - **Functional composition paradigm** - React composes views (pure functions) while Redux composes pure reducers (also pure functions). Output is predictable given the same set of input.
 - **Easy To Reason About** - You may have heard this term many times but what does it actually mean? We interpret it as having control and understanding over our code - Our code behaves in ways we expect it to, and when there are problems, we can find them easily. Through our experience, React and Redux makes debugging simpler. As the data flow is unidirectional, tracing the flow of data (server responses, user input events) is easier and it is straightforward to determine which layer the problem occurs in.
-- **Layered Structure** - Each layer in the app / Flux architecture is a pure function, and has clear responsibilities. It is relatively easy to write tests for pure functions.
+- **Layered Structure** - Each layer in the app / Flux architecture is a pure function, and has clear responsibilities. It is relatively easy to write tests for pure functions. You have to centralize changes to your app within the reducer, and the only way to trigger a change is to dispatch an action.
 - **Development Experience** - A lot of effort has gone into creating tools to help in debugging and inspecting the app while development, such as [Redux DevTools](https://github.com/gaearon/redux-devtools). <br> ![Redux Devtools Demo](images/redux-devtools-demo.gif)
 
 Your app will likely have to deal with async calls like making remote API requests. [redux-thunk](https://github.com/gaearon/redux-thunk) and [redux-saga](https://github.com/redux-saga/redux-saga) were created to solve those problems. They may take some time to understand as they require understanding of functional programming and generators. Our advice is to deal with it only when you need it.