cramming is not understanding
The idea of studying before an exam to memorize texts and facts is called cramming1. There is, however, a distinction to be made between feeling our brains with short-term memories that are useful to overcome a test, and understanding (see: hermeneutic circle). Cramming is short-term and whatever knowledge we acquire will probably be lost few days after the test.
Understanding, however, relates to how one links new knowledge to existing one, or how can one switch contexts (see: writing down as a mean to understanding what we read).
The extra topic is related to how we access what we learn. spaced repetition may help boost specific memories, but what about more abstract connections, like the ones needed to build up theories? Ahrens makes the distinction between retrieval and storage strength, and moreover, he claims that The Luhmann method creates an in-between flash-cards and mental models.