Earlier quoted context omitted.
You do not need to shred books to scan them. This only happens if you don't care about preserving the integrity of the books and you want to scan more cheaply.
But their legal framework for being permitted to scan the books en masse (they are "transforming" the book from physical to digital) requires destruction of the original. Otherwise it wouldn't be transforming, it would be duplicating.
Then, should we hope they do not do backups, as they would be duplicating. And that they delete the files (zeroing from the disk) when such books are loaded into memory as technically it would be duplicating also. The same if they use different machines simultaneously.