You have an institution - in this case the Ministry of Justice - who presumably at one point had senior employees who were acutely aware of the historical importance of preserving original documents like this. These were likely key values of that organization, but crucially they were recorded only in people's heads.
Time moves on, employees come and go, and now there's a push for savings around the UK government and someone pipes up and says "well, we could digitize those musty old documents, throw away the originals and save on archival costs" - and there just so happens to be nobody currently in a senior position who understands why that's a bad idea.
I have the same suspicion every time a tech company makes a howlingly obvious error - like that time GitLab said they were going to delete every free repo that hadn't been updated in a year (and later recanted after the entirely predictable outcry): https://www.theregister.com/2022/08/05/gitlab_reverses_delet...