I've used an inch of licorice stick in belgian pales and saisons. Light licorice / anise flavor. I believe the sticks are derived from anise. I've used more stick in a few variations of Tumultuous Porter. I could see using an inch or two of stick in a dark witbier. And there is an ancient (70s) recipe for a stout by Dave Line that calls for an entire stick. I've never brewed that one though.
And I've used an inch or two of stick and a quarter ounce of root in an old porter recipe featuring brown malt.
I think the root is subtler and adds a sweetness that doesn't ferment out. I may have to try it in an oatmeal stout.