This is the opposite of a book burning. These books which only a few would ever know the names of, let alone find, let alone read, are being digitised so they can be found in electronic searches.
You make it sound like they are running a second Project Gutenberg. They most definitely are not making these available for electronic searches. At least not searches the public can participate in.
I would say “reduced”
What guarantee do we have that the book contents will be served unfiltered and unaltered?
They are creating embedding vectors and training documents - changing whatever they want - and destroying the original copy so nobody knows what was actually said.
It is just like book burning.