Why the need for imutable data in React?

Study and React Redux. Got to use imutable data, but can't understand what they need. In particular the library imutable.js.
Understand the following things: connect picks up changes in store and is updated only when the data in the store are new, not mutated. Well, OK, what's the problem in the reducer at a certain ActionCreator return a new object/array data?
What do the data immutability? Why use imutable.js? Where is the profit? Please explain in detail. Don't quite understand this answer as "Less of a headache."
Thank you very much, all good :3
June 7th 19 at 14:42
1 answer
June 7th 19 at 14:44
There is no profit, do not bother.
When "profit" from immutable will loom on the horizon, you'll already be ready for it (or will face some problem and will immutable, or just improve the theoretical basis and complexity of the problem). As I understand it, using immutable and without use .toJS() - search in the structure of your data will be faster.

p.s. if you find the video, there was a presentation. is not found.

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