The intent for the "Links" parameter is to allow linking from an Actors: page to the actors page on a wiki for franchise outside of the shows, films, games, etc based on DC properties. The general rule of thumb is that the actor made a significant contribution to, and is better known for their role, in that franchise. Examples of this are Mark Hamill and Star Wars or Michael Dorn and Star Trek.
Linking an actor like Alan Ritchson to the Smallville wiki is redundant since Smallville is with the scope of this wiki. And taking a sample of the actor articles over there, it does not seem to be anything additional, related to Smallville that is added.