Because it's less crowded, a mixture of terrain from easy to difficult for progression, and they get a lot of snow.
Anyone will tell you that it's easier to learn on 6 inches of powder then it is on an ice ball ( =
Being less crowded just helps with mental clarity and less reacting to people around you, and helps you get a lot more runs in.
"When I do good, I feel good; when I do bad, I feel bad. Thatís my religion." - Abraham Lincoln