The more mysterious an actor is, there’s more curiosity. I’ve seen non-actors play a part in a mediocre movie but come across as a good performance.
There’s less probability to come across as fake to the audience, as opposed to a verbose character trying to be convincing (character running for public office), and many more attempts to err.
Also, there are a lot of people in real life who are quiet. But in a movie, it’s obviously condensed, so all you hear/see is an actor talking or demonstrating some sort of action, even with inaction sometimes.
I wonder if you have some specific examples in mind? The first thing the OP made me think of was singer Sam Phillips’ performance in Die Hard With a Vengeance as the slient girlfriend of the villain.
Then I thought of some of the great silent comic characters, like Harpo Marx, Mini-Me (as played by Verne Troyer in the Austin Powers movies), and Silent Bob (as played by Kevin Smith in many of his movies).
I have recorded an early Harpo Marx movie appearance in Too Many Kisses (1925). Harpo has lines and speaks. Unfortunately it was a silent movie so we can’t hear him.
Another example that comes to mind is Teller (as in “Penn &”), who said he stopped speaking onstage early in his magic career because the audience paid more attention that way.
Plus, it generated a lot of buzz. As far as schticks go, not talking is an interesting one. A while back, America’s Got Talent had Tape Face, which similarly created a lot of buzz. And, like Teller, Tape Face does talk, just not during his performances.
I mean for the filmmaker there is a huge advantage, non speaking roles can be given to non-union extras, which saves them a fortune
I think? Is there some limit on the amount of acting that a non speaking role can perform before you need to hire a real (Sag-afra affiliated) actor to do it?
Taken to the extreme by a remake of The Miracle Worker. They would have given the actor who played Helen an Oscar for her very moving performance, except she was an extra and they don’t know who she was