Yes, the majority of content would still come from bigcommunity/c/books, the crucial difference in that system is that posting in otherserver/c/books would get the same probabibility of being viewed by random and non logged users.
I cannot emphasize enough how important that is. It is the only way to break the stranglehold that bigcommunity/c/books will always have over almist every lemmy users.
Without this, this is just reddit all over again. Meet the new boss, same as old boss.