It's too bad the vision depicted at the beginning of the article (full texts potentially available in all libraries), didn't come true. But I feel that the public did get the most important benefit from the project: the ability to search these books. I've been researching a history of science subject recently and it's amazing the amount of information I could get from Google Books and nowhere else online. And where the snippets are not enough, I have the book title and author name, so I know where to look for the information in print.
The public benefit of searching the books isn't fully realized, alas, until more than just Google can see all of the text. Here's an example of a book discovery tool built using the Internet Archive's scanned book collections:
