Bookshops selling through chat run into a particular problem: a catalog that's genuinely large, customers asking about a specific title that may or may not be in stock, and no easy way to search back through old messages to check what was actually confirmed.
The first is a real catalog a customer can actually search and browse — by title, author, or genre — instead of asking "do you have X?" one book at a time and waiting for each answer.
The second is stock that reflects the real copy count. A bookshop with two copies of a title in stock can't accidentally sell a third — the listing simply stops offering it once it's gone.
The third is multi-book orders arriving itemized — five different titles in one order, each with its own price — instead of a seller tallying a list by hand from a chat.
The fourth is customers following a series or an author, reordering straight from their order history when the next volume comes in, instead of retyping the full title and author every time.
The fifth is delivery versus pickup, chosen by the customer — useful for regulars who'd rather swing by than wait on a delivery for a book they're eager to start.
A good bookshop still earns its regulars through recommendations and taste. What an itemized, searchable order does is make sure the exact title someone asked for is the exact title that gets picked off the shelf.