Without any idea of what ZKP is used for, I did not find it the explanation very intelligible. Later I found the simple explanation on Wikipedia and was able to connect the dots https://simple.wikipedia.org/wiki/Zero-knowledge_proof
> Peggy, being a very private person, does not want to reveal her knowledge (the secret word) to Victor or to reveal the fact of her knowledge to the world in general.
Without that, the example seems overly convoluted.