I can see "maybe" two uses for them. That is a big maybe though.
On the revolver calibers:
If you shoot a lot in one particular gun. If that gun has loose chambers, AND you hate lubing cases when resizing. Better fit and a better bullet pull might be in order. Can be equaled with a good steel die though.
On the pistol calibers:
If you shoot a lot in guns that leave a "glock smile". One pass with this die would smooth out the smile. It is suppose to size all the way down. In this case, a good pass though die would result in the same result.
