I think that must be an Amazon data error – I have the first three volumes and they’re about 230 pages each, so pretty short by LN standards. (My volume 1 I picked up in a bookshop on a whim and it’s signed by the author…) I guess on balance I’d recommend it if the back cover blurb/series premise sounds interesting (I did read the first three books in the series) but it’s not a book I’m “you need to read this right now” enthusiastic about.
A bookshop-book I can recommend more full-heartedly is the ビブリア古書堂の事件手帖 series, which I liked a lot – interesting individual stories centring around different books or authors, and an overall series arc which knows where it’s going and doesn’t outstay its welcome.
Rating books you dislike, likely rating them low, seems a bad idea to me.
On a platform like this one with not too much or hardly any ratings for some books, this kind of ratings could really throw off future readers that actually might miss out on something they could have loved.
As for me, I only read what I love, so I don’t have this issue. Of course, there are times when I stumble across books where I thought those were meant for me - but they weren’t. Well, in the case a book that did promise something and it did not deliver, bad ratings are natural. But I never consciously choose books I won’t enjoy, no matter what.
I think it’s fine to rate stuff you didn’t like. Might as well make use of all 5 stars, and a negative review is just as valid as a positive one. Personally, I’ve been both disappointed and pleasantly surprised plenty of times when it comes to recommendations for or against things, so nowadays I prefer to just find out for myself than decide based on ratings, especially when it’s for something as subjective as entertainment. If someone would have loved くちべた食堂 | L22 but didn’t read it because I only gave it 3 stars and they only read things with 4+, that’s kinda on them. They have their own agency to read what they want and shouldn’t even let a general consensus sway them that much, let alone a single opinion.
Otoh if that book only had 2 star ratings (and no reviews), left by people who don’t like cooking manga, it would be understandable for someone does like cooking manga to assume it’s just a bad cooking manga. In that case, I think the hypothetical raters should have left a review explaining; or just not rated.
I hear you about just finding out for yourself though. I’ve read plenty of reviews - good and bad - (mostly on other sites) where I’ve wondered “did we even watch/read the same thing?!”
When there are less than 10 star ratings, you really can’t assume anything from that. There’s going to be too much bias in the sample (even with 100 reviews, to be honest, but that’s not the kind of numbers we have on the site yet). In general, rather than the overall star rating, I check the ratings of other readers I know have similar tastes to mine. If none of them rated, it’s the same as no rating for me.
The star ratings I leave are mostly for myself. My main use for my library is to find books to recommend to other people or series I want to keep reading. In both cases, what matter is what I felt about the book, not what the general consensus is. For that reason, I will give low ratings to stuff I didn’t like, regardless of why I didn’t like it.
There can be a kind-of amorphous consensus that some books are great and amazing - but if you didn’t enjoy it I’d appreciate seeing a 1-star there. Don’t leave me to stumble into something you didn’t enjoy just because “everyone” reckons it’s great, or are rating it on some “objective” rating system that doesn’t actually take into account how enjoyable it is to read.
And I don’t think there’s anything to be gained by holding off on rating things negatively because their genre isn’t something you’d normally read. If you enjoyed it, rate it highly, and if you didn’t - rate it where it belongs. Not everyone considering getting that book is there because they love the genre either - if I’m considering some shoujo romance book because of the cover art or whatever, I want to see your “I didn’t like it” 1-star review and not just 5-star reviews from the hardcore shoujo romance crowd.
Of course, it you want to actually communicate to other potential readers, leave a review. “I can see why other people like it but personally I was bored to tears” is a great, complete review that tells me infinitely more than your star rating.
(even then I still found some things to appreciate)