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.
The biggest problem I have about not getting an offline copy is that he makes it clear that if the book does not perform to his expectations, then he will take it down.
So, even if I pay for this wonderful book (and it /is/ wonderful!) and nobody else/not enough other people do... And then it's gone!
Luckily there are browser extensions like Stylus [1] to help fix these design decisions that don't account for those of us with poorer eye sight or older screens.
Well, does the author supply a bundled html for download? I don't like paying for things that can vanish any day, you can open a pdf viewer side-by-side a code editor too.
He has strong opinions about typography, period. It's not just about Kindle or any other device or format. I do recall asking about a PDF or ePub version of Practical Typography [1], but he refused saying none of the eBook formats are good enough. While I understand that to some extent for a book on typography, I don't understand it for a book on programming.
eBook reader typography - my experience is drawn from using a Kobo with various EPUB & PDF from multiple publishers - is almost always terrible.
Among other things, code listings tend to be a mess. It's frustrating when technical publishers release digital versions of their works, and the code snippets (for example) turn out to be PNG files. That works great for a PDF intended to be printed on paper, but doesn't scale well to an ebook reader.
Well, the main claim to fame for the Kindle over, say, an iPad (or even Amazon's own Fire tablet) is the e-ink screen. It really does make a difference in reading fatigue in my experience, I suspect because it's lit like paper, i.e., by reflective light. And, of course, the e-ink screen also means that it runs weeks without needing to be recharged.
I've never been able to understand this. I read from screens nearly all day and I've read books for many hours in a row on normal tablets. I have to wonder if this is nothing but a nocebo that will stop being a "thing" once screen reading is more common, like alleged motion sickness from normal television.
People tend to blink less when looking at a bright, backlit screen than they do when looking at a passively lit screen. The eye is dryer when you blink less, and thus more easily irritated.
"Computer Vision Syndrome" brings up 250,000 hits on Google Scholar. I'm skeptical that it's a nocebo at this point.
Even if reading from a backlit screen doesn't bother you, you have to recognize that reading outside is much better on an e-ink display.
I have a Kindle and I like it because it's small, the battery lasts forever, it's single-purpose, its inexpensive, and is usable in all lighting conditions. Of course you can come up with an equivalent list for your tablet, but the reasons will be different and those differences are enough to justify both products existing.
I strongly prefer reading on an eInk display. I work on a screen all day, but I'd definitely choose "Not reading a book" over "Reading it on a computer display" (a paper copy is still the best reading experience, though -- just less convenient for storage and other such things)
The other pro for the Kindle is that if I put it in flight mode, I need to charge it once a month or so.
I'm a big fan of rotatable monitors. A 4x3 display rotated to portrait is fantastic for reading most PDFs, if you set Acrobat to Fullscreen and Single Page View.
As a bonus, lots of offices have a closet full of old 4x3 Dell flat-panels somewhere, so there's no hassle with procurement.
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.