Indeed, I have read a good many books but very few of them I'd find worth using in class. There are issues to consider like the topic itself, the amount of valuable language, the register, timing, etc. but more importantly, the outcome. Idiomatic language - that's what your example is about - is a good thing to master in general but if it's time-consuming there's little value in it. No one could deny that reading novels takes a lot of time, could they? Of course, it depends on the amount of hours available...
Let's see what others say..
ps alternatively, it would be nice if you could share the way you use novels in class
I do not say I search for them to use in class. I will use them neither in class nor as a homework to give my students. I will just suggest them to my students who ask for books individually for improvement in English