The Pin behaviour is not going anywhere, don't worry about that. It is too widely used to even consider getting rid of it.
I guess that "replacing" was the wrong term to use.
What happens is, scene graph transformations solve a lot of the problems where the Pin behaviour fell short or was too cumbersome to use. So in that sense it is a replacement.
Having said that, both features are widely different in their inner workings, so the Pin behaviour can never really be completely replaced.