The target of the scammers is someone browsing Amazon, who isn't going to know to look for an NFT. Someone familiar with the author is just going to check the author's website and see the list of books they've published.
It's also worth mentioning that the OP of this comment thread promised a solution that any author could implement without Amazon's involvement, presumably because Amazon is disinterested or disincentivized to care.
Or it might come with an NFT created by the scammer, which they might trick the reader into trusting with social engineering.