With React, the point is that by simply comparing the reference to immutable objects you can skip most unnecessary re-renders almost for free. Of course you'll

With React, the point is that by simply comparing the reference to immutable objects you can skip most unnecessary re-renders almost for free. Of course you'll still have some false positives (ie, the reference is different but the content is the same, and re-rendering wasn't necessary) but that's not a big penalty.