Everyone agrees rare books and manuscripts need to be kept, which the article admits, so that's not an issue.
So ultimately the question is "regular books" and the crux of the article's argument seems to be:
> One glaring problem with libraries’ increasing their reliance on digital texts is the relatively large number of errors in the Google Books corpus. As archivist Paul Conway has shown, “the imperfection of digital surrogates is an obvious and nearly ubiquitous feature of Google Books.” But, even overlooking the outright errors in the scanned pages, my point is that “content”—what books contain—goes far beyond words in a particular order and beyond page images of a single representative copy. As we detach texts from books, we enable a certain range of procedures while disabling others. Online editions can offer up texts for investigation and discovery, but they are not replacements for the material they represent.
This makes no sense to me. I've never seen an "error" in a Google Books page image. The OCR for sure, but who cares, and that can always be redone. And in terms of "enabling a certain range of procedures while disabling others", online enables a ton, while I'm at a total loss of what is "disabled". Again -- for rare books and manuscripts, of course. A beautiful gilt binding, absolutely. But for just your everyday workhorse books that make up 99+% of a library's content... I just totally and utterly fail to see anything being lost at all. (And so many original covers/bindings are replaced with generic library covers/bindings when acquired, so it's not even that.)