Why did you consider buying the Kindle version rather than the paperback? Because it's more convenient? Maybe that's why they're able to charge more for it.
The author gets paid, the publisher gets paid, you get the copy you want with less resource waste than scanning it for yourself.
Anyone have a moral objection to that they'd care to elucidate.
By torrenting a work you own in a different format, you are (potentially) also distributing that work to someone who doesn't already own a copy.