The purpose of the tables is to fuel other queries/reporting procedures/export functions. They're just recreated everyday because the raw data changes from day to day, and Access is the medium in which such reporting is conducted.
A delete-and-insert approach would accomplish the same thing, but problems would arise if the insert query can't be completed for any reason. I would have deleted the contents of the tables, and it's typically better to at least use one-day-stale data than no data at all.