Hello Ivy!
I guess advertising and promotion makes a book over hyped to some degree. And sometimes the title itself makes it enticing and this is actually normal to some authors to make the title captivating, if not, nobody would care buying or reading that book just my knowing the title.
We really don't know what's in the book when we haven' read it yet.
The moral lesson maybe is:
Try to get something from a book maybe values or virtues that would be applied in daily lives for improvement.