Meaning what, that movie adaptations are not necessary? I know that.

The posted list put Dune in with movies that were made based purely on the success of their predecessor, which is not the case for Dune.

Now, while the sequel wouldn’t have been made if its predecessor hadn’t been successful, the books are the driver behind making the movies.

Dune messiah a franchise exploit? How?

It’s based on the next book in the series. There is a reason for it to exist beyond making money.

WHAT CAN THE HARVEST HOPE FOR, IF NOT FOR THE CARE OF THE REAPER MAN?

It’s also very often used as an argument against rehabilitation in prisons:

If free will exists, then crime is a choice. If you choose crime, you are a bad person, and punishment is the only way forward.

If you commit the crime again, it’s because the punishment didn’t work, and/or because the person is simply bad, so a longer punishment is needed, and infinitum.

It’s also used to justify the death penalty, which would not make any sense in a deterministic universe.