I'll answer in various frames:
- product development: why make someone "do one extra click" when you can make the extra click unnecessary?
- writing: respect your audience's time.
- humility: take one minute of your time to save other's time.
- databases: optimize for reading not writing
Two things, in the spirit of answering your question and explaining myself.
1. The argument above is sound, but it overstretches my metaphor and sidesteps my point which is: "if there is negligible cost in helping a customer, do it." Stated another way: "if reducing ambiguity helps a customer and has negligible cost, do it." (If a one word change reduces some ambiguity for some people, that's an easy win. Copy-editors do this frequently.)
2. Another angle: broadly speaking, I'm asking the question "What is better?" not just "What is necessary?". The first motivates improvement, no matter where you are. While the latter can sometimes be pragmatic, too often aiming only for 'necessity' justifies the status quo.
Would the extra click really be unnecessary?
The ones who don’t care about the book don‘t click anyway.
The ones who are interested click no matter if it’s an upcoming or already existing book.