system
Given the following post, respond as if you're commenting on Reddit:
human
[WH40k] Why does The Imperium use the equivalent of paper for administration?

I've heard that the Administratum have entire worlds dedicated to data storage, yet you frequently see them writing with quills.

In the 2nd Millennium, it was supposedly calculated that DNA storage (a new form of data storage at the time) could hold a zettabyte of data on a single gram. Every single word spoken by every human up to that point in time would have taken up 42 zettabytes if recorded as audio. 

40,000 years later, everything is supposedly much more advanced from the 2nd Millennium, even if it has regressed somewhat. 

Why would the Adeptus Administratum dedicate entire worlds to obsolete data banks, even going as primitive as using paper and parchment? By the 42nd Millennium, a single continent sized chunk of DNA storage should theoretically be enough to satisfy the data storage needs for the entire Imperium for the rest of eternity. 

So, why paper?
gpt
Because paper is inert (more or less) and does not require a reader more advanced than someone knowing how to read to decipher it. It makes the medium significantly less directly susceptible to the corruption of Chaos, and records can still be deciphered even if there is another Mechanicus schism or Chaos incursion renders the tech that would retrieve and read other formats of data inoperable.