Why MonetDB uses Materialization

Hey All, Thanks for the great open source project.  So while going through some materials  in a CMU DB course I saw it mentioned that MonetDB uses full materialization, and this is a bit weird since in c-store potentially scanning a billion columns a full materialization may take a lot of time and the classic volcano model might be better. Can you guys please explain the rationale ? These are the slides :- https://15445.courses.cs.cmu.edu/fall2019/slides/12-queryexecution1.pdfMonet... is mentioned in Slide 11. Thanks and Regards