According to the Nokian site, R8s are studded--they may or may not have studs actually installed (that's typically done at the tire dealer, not the tire manufacturer). Tires that are designed to work with studs need to have enough solid areas to hold the studs in place. This limits the amount of sipes that they can have.
There are three things that make up effective winter tires: flexible belts that conform to the irregular road surfaces found during winter, tread compound that is flexible in the cold, and blocks and sipes. Sipes are what make traction on ice possible because they wipe away the film of water that makes the ice slippery. (The colder it is the less slippery the ice is.) Studs dig through the film of water to get traction on ice, but in every other winter condition they make traction worse because they hold the tread pattern off the road surface. They are also hard on pavement and are linked to increased rates of lung cancer.