Books have limited print runs. Many books in libraries are only borrowed and perhaps read a few times. Niche titles more so. Books go out of print and are hard to search for arbitrary text.

But digital can also be lost. I think my point is that digital isn't a clear line in this situation

The ease of making copies of digital data, the ease of indexing them is totally different from books, just as writing, clay tablets, scrolls and books were from a purely oral society.

We can "what if" ourselves into any position we want. The fact is that digital surveillance is here and does collect information about people in a scope that is qualitatively different than putting information in books.