Butterick has Strong Opinions™ about Kindle typography that led him to that position. I largely share those opinions, to be fair, although I think it's a bit of a quixotic enterprise for many books; offline is more important than beauty. (And, really, the Kindle
could do most of these tricks if Amazon gave a rat's ass; Apple's iBooks can do nearly everything that any other WebKit browser can with regards to typography.)
Having said that, though, this is a book that I'd argue is better in the browser than on the Kindle or as a PDF. I want to be able to read this with a code editor open, and the book side-by-side in a separate window. PDF books don't reflow, and in my experience Kindle just isn't particularly good for tech books.