Re: Scarlet Witch,Quicksilver,and Polaris
It depends how you define their importance. But some people here don't read every comic-book that was released by Marvel.
People who haven't read the comic-books are more familiar with Quicksilver/Scarlet Witch being part of the X-Men world simply because of the videogames that were released and the cartoons that were aired in TV. And they were also depicted as Magneto's children in those videogames and cartoons.