Why do we need Control.Monad.Instances?

[Henning Thielemann]

On Fri, 11 Nov 2011, Bas van Dijk wrote:

> I forgot the reason why we need Control.Monad.Instances which exports
> orphaned Functor and Monad instances for ((->) r), ((,) a) and (Either
> e):
>
> https://github.com/ghc/packages-base/blob/master/Control/Monad/Instances.hs

Compatibility with Haskell 98's Prelude?