@forteller It's mostly available on other servers, but there's an extra step. When I search a book and it's not on my home instance, there's a button I can press to search & import from connected instances. So if you added a new book to an instance connected to mine, I would have access to it if I took the extra step. (The extra step is really no trouble at all, I've imported 10+ books from other servers, and only had to add one book manually.)
(Caveat: just a user, might have this wrong)