The problem I have with zlib, is that it's addictive... Always when I'm looking for a specific book, I find myself roaming the whole library for things I actually don't need... (Cooking, crafting, knitting, catting...whatever)
Thankfully it's limited to 10 books per day and I think it should be further reduced to 10/month or something like that. I'm a fucking hoarder and this thing would take my whole life in no- time.