Was it, like some users put it, extremely huge and valuable housing all the knowledge in the world, or was it just a normal library housing books?
Would society be super advanced if it hadn’t been destroyed or would it not make a difference?
That library in the Nile Delta has an overblown place in popular imagination. I commend to your attention this answer from u/XenophonTheAthenian, and this one from u/Naugrith, both of which expound on The Library.