Questions with React.PureComponent VS "react-immutable-render-mixin"

[freezen]

Hello,

I found this open source from a link in a blog some days before. The blog said this repo is very helpful for performance.
Currently, my project use Immutable & PureComponent, and use Immutable.is() in componentShouldUpdate func to check if need re-render in each component. So if I try to use "react-immutable-render-mixin" in my project, will it lead to some benefit?
Could you simply clarify that how this repo do within the componentShouldUpdate or other
implementation?
I know that users are urged to use PureComponent, but I still want to know some deep implement here in "react-immutable-render-mixin", and know why "urged to use PureComponent" and what is the diff?

Many thx