I’ve gotta say ultimately I’m not convinced Herb put more thought into it beyond its purpose justifying human labour in his universe despite the massively advanced technology. There’s a similar shortcut in the Warhammer backstory.
Herbert did genuinely believe that people overly relying on machines is problematic insofar as it "trains the mind" to think like a machine, and in the process loses the indeterminacy that he believed to be an inherent and valuable trait of human thinking that machines cannot replicate.
(Coincidentally, this is also the main threat in the original books, just manifesting in a different form, with prescient individuals "locking in" the rest of humanity.)
