One of powerful features of Spark SQL is dynamic generation of code. Several different layers are generated and this post explains some of them.
Even if Project Tungsten was started in Spark 1.5 and Spark's current version is 2.1 at the time of writing, it's good to know what precious this Project brought to Spark.
The use of Dataset abstraction is not a single difference between structured and unstructured data processing in Spark. Apart of that, Spark SQL uses a technique helping to get results faster.
