I worked on a similar project, with thousands of books to organize. We did just that, because it seemed common sense. We had a couple of issues:
1. We found that sorting books by category took quite a lot of time. For every book we had to spend a couple of seconds deciding in which category it should go. By the time we started wishing we had put them all together, sorted only by alphabet, it was already late.
2. Shelving books alphabetically is a problem when they keep coming and going. How do you know how much space to leave on the shelf for a specific letter? Maybe now you have 10 books by Stephen King, but the next container will have 50 more. If you don't leave enough space you'll have to shift all the books after that letter.
This is what card files were originally invented for— number all the shelves, put your new book wherever there’s room, and put a card with the title and shelf number in a sorted drawer. When you get rid of the book, get rid of the card.
Shelving in instead central to many specialty shops!
Twenty unsorted banana boxes: every book just becomes a blur (as in, “Oh great, another Danielle Steele novel, and another bible, and another Excel 97 for dummies, …”).
Most people do not enjoy that more then once or twice.
In a bookstore, this is a virtue. But we appear to be dealing with a book barn. Perhaps the patrons of book barn have not wandered in by accident while searching for a bookstore :)
For OP: I think you might be better off photographing the ISBN and then using a service or script to do a lookup and associate that with a cover and title. Various editions might not have their covers recorded in a database, and titles will give many dupes, but an ISBN will uniquely identify a book.
Additionally, OCR'ing stylized text is problematic. I wouldn't expect easy reading of covers, particularly of used books.
The answer to this is important in order to properly size the effort. If the goal is to impove the business efficiency of the store, then it should be seen from ROI stand-point. Even the fellow customers/rummaggers could be engaged with a right incentive and tools. Otherwise, the next estate books container shipment will negate the gains of ordering.
Basically, is OP ready to overhaul the operations or is just willing to do something nice just for now?
Ideally, a book cover and info page should be scanned/photo'ed on first touch either by receiver or shopper and sticker coded somehow as processed, then left wherever. In case any jewel-worthy titles uncovered from OCR, the book could be located (stickerwise, date log, crate, whatever) and brought to prominence and priced as appropriate.
Unleashing imagination, as an incentive and QC strategy - some sort of automated OCR and lookup could locate the pointed book on amz or elsewhere and thus reviews and going price vs rummager's deal.
Either way, I'd see this more of a business question, rather than a technical one. Donating a technical solution is fun, but without changing the operations process is not going to be sustainable.
I've seen a few of these, and the basic minimum difference between "pulp waiting to happen" and "bookshop" is basic shelving. Different shelves by category: fiction vs non-fiction and their subdivisions. Within the shelves, alphabetise. Now it's possible for browsers to actually find things. When you put them on Amazon this will also help find them for shipping.
This process will also help you find the stacks of duplicates. You'll have a crate of 50 Shades and Twilight and Stephen King. The Stephen King will eventually resell; the others won't.
This page from the excellent Barter Books on their acceptance policy may be of some help: https://www.barterbooks.co.uk/html/About%20Us/Incoming%20Boo...