Not the author, but it seems like they are saying that, at first glance, it seems unreasonable to spend millions of dollars on a physical structure to hold book

Not the author, but it seems like they are saying that, at first glance, it seems unreasonable to spend millions of dollars on a physical structure to hold books when all of the same information is housed online and accessible digitally. But, upon further consideration, there are secondary benefits that make a library a net benefit for the community.