Perhaps it's a form of copy protection but IMO, without it being digital, DRM isn't possible.
I did purchase this book because the last version has so many good reviews and I too would have preferred a digital copy but to me, calling it DRM is technically incorrect and smells like bait. I'm mostly disappointed that I fell for it.
This discussion hinges on some pretty fundamental questions of what is "a book," whether you can protect digital rights by not having a digital form, and whether the term DRM is understood to mean any kind of IP protection. I think there are reasonable answers to all of those that would have people falling on both sides of the question.
If physical only was done to prevent piracy, it is at the least a "RM" move.
Seems like they're shooting themselves in the foot, creating a bigger incentive to scan the book and promoting the distribution of unofficial digital version of their book and not getting a dime for those.
Now, not only they made themselves look bad, show they misunderstand the digital world but they will also pass on a whole market.
Really? That's the last point of three. I gave more weight to this one:
"Creating and proofing each ebook format is not a trivial effort. It involves reformatting every code sample to work on every ebook reader, accounting for differences in screen contrast, accessibility testing, and proofreading the text and code samples several times on each device. Instead of spending our time struggling with reformatting, we're choosing to focus on improving the technical material."
(my reading of their statement is that print only was mostly because of piracy)