Why, often in film credits, are the actor’s and character’s name often written as, for example, “Ian McKellen – Gandalf (as Ian McKellen)”, but only for certain cast members?

Question

I’ve seen this a lot on IMDB, and this was just an example using more well-known names. For a direct example, I was looking up the cast for the 1999 film, DragonHeart: A New Beginning, and the lead actor, Chris Masterson, is listed as “Christopher Masterson – Geoff (as Christopher Masterson)”, and another character is ” Vladimir ‘Furdo’ Furdik – Sentry (as Vladimir Furdik)”, but only those 2 actors were listed that way. What does it mean that their character is “as the actor”, but it’s only true for them and not anyone else in the cast?

In: 80

Answer 1

In the final credits of the movie, the department of redundancy department credits the actor with the most credentials in the credits by crediting them twice in the final credits.