@clarys I got hooked on Bookworm recently and the point of no return for me was the last 3 episodes of the anime.
The story was nice and all, very interesting in fact, and suddenly there is the trombe extermination with the Knights Order.
A downpour of science fantasy out of nowhere, a new part of the world that's released and then... it stops. Mindblowing.
It's really inviting you to pick the next book to know what's happening.
And as the books are much better than the anime...
(well, I'll skip the part where I've been reading day and night for weeks in a row, I ended up so exhausted that it's a bit embarrassing)
But should you warn your friends of AoaB's possible addictive effects?
To convince someone to read it, I would use an argument based not on reason but on feelings, that it really brings sparks in one's life. And as it's a long lasting serie, getting Bookworm sparks every weeks for a long time is definitely worth the investment!