The book aesthetic was important because it is a religious text, and also because anything like what we would call a "computer" is not only banned, but seen as unholy. The story of Dune is one of religion, ecology, the fallibility and fatality of prescience, scatterings and exoduses, failures of humans, how mankind matures and develops over a 10,0000+ year period. The actual technology mentioned is often in passing, is often intertwined with some human ability, and almost never a plot device like in so many sci-fi stories (Death Star anyone?).

I believe that the technology in the book must be viewed through the lens of The Butlerian Jihad events of the Dune universe, and the commandment of not making a machine in the image of the human mind. It isn't retro-futurism, it's human-centric technology.

In the later books, shigawire is also mentioned as a data storage method, so I don't think it was a lack of imagination.

Herbert quite deliberately planned the Dune universe to be seemingly technologically backwards to remove the crutch of technology and focus instead on human potential.

Exactly, and this is why I think the series is such a standout.

Yeah, sorry, that's what the parenthetical about "this particular case" was supposed to allude to; that in this particular context, there were a number of reasons why this book took the form that it did