The use of the word "pearlite" essentially means that the cast iron has been cooled slowly. This gives the metal a more relaxed structure and makes it less prone to distortions with subsequent heating. They could have quenched the iron (or skipped an annealing step) for faster throughput, but decided to go with quality over quantity.
The pearlite/aluminum cylinder uses a cast iron sleeve instead of plating the aluminum cylinder wall with Nikasil or chromium. The sleeve is typically 3mm thick and makes for a much more durable cylinder than some of the plated materials. It is often cheaper to produce too. It does have drawbacks with manufacturing yield though.
The pearlite/aluminum cylinder gives you all of the benefits of a cast iron cylinder (re-honeing) and the weight savings of aluminum.
As a side note: Avoid Nikasil coated cylinders in the US. The sulfur content in the gasoline here is too high and will erode the cylinder lining fairly quickly. Also avoid using sulfurous 2-stroke oil with Nikasil coatings.