It may very expensive in time and resources to scan it all even if it is just the covers. You need to work out how long it takes to fetch a book from the barn or container, flatten/unbind if necessary, scan the cover, rebind, and put back. Then multiply by how many books...

I worked at a small startup in the early 2000s that somehow got massive contract to digitalise a Middle Eastern Oil & Gas company's very very extensive documentation library. We had an e-learning product where you could use a scanner to digitalise a printed book into online documentation.

Demos of scanning a book or two was really impressive. So surely scanning more than a million books/manuals/charts will be just as easy. Not quite.

Think we calculated it would take years as the bottleneck is the manual unbinding and re-binding before and after scanning. Scale that to a million and it was not the 2 months project initially forecasted. Buying more scanners and hiring more local staff scaled that part horizontally and improved the speed but still a long project.

However the client "forgot" to pay us for a few months, the bank and our accountants forgot to check and we went bankrupt soon before we really got started. Though at least I got a trip to the Middle East for a few weeks.