Is this really the correct translation? In Swedish there is a direct translation: Es lohnt sich --> Det lönar sig.
The Swedish translation is almost unequivocally related to money and you wouldn't say that if you mean that the book is educating, rewarding or fulfilling, which are more plausable descriptions of a good book rather than to say "it pays off" (unless it's a business-related book of course).
It sounds very awkward to me anyway.
Is "det lönar sig" really not used for anything else than refering to money in Sweden. I am a native swedish speaker from Finland and we use it mostly when talking about things that are worth doing to achieve/gain something. For example: "Det lönar sig att komma i tid." "Det lönar sig att lära sig flera språk."