[Studio717]

I've been using many of the public domain PDFs from Google Books (and a few from Internet Archive) for my research, books that I could access no other way.

The older the book (or item, such as a pamphlet or manuscript), the more reason to digitize it, imo. They are often fragile due to their age, or so rare, that many libraries have held their holdings so close that very few could actually access them.

Once those books, etc., are digitized, then most can be preserved even more efficiently since accessibility will not be required by any but those who are researching the physical form itself. The information contained in the item will be available to many more people, though this will challenge the nature of academic libraries' 'ownership' - control of which is something a few out there are not willing to give up.