I am an instructor at a couple of colleges, and have been teaching for the better part of 15 years. And my experience with technology in the classroom tells me that DPS is too closed an environment to succeed as an instructor tool.
One college where I teach gives every student a free iPad, and ebook versions of reference books from a respected publisher. Even though the college administration is trying to enforce the use of these books in the classroom, most instructors and students do not see the point of using the platform in that way at all.
DPS produces closed-off apps which resemble classical flip books and offer relatively shallow interactivity (unless html/css/js produced content is added), and it takes a lot of effort and skill on the part of the instructor to create a half-decent result. They are also relatively difficult to update in terms of content (compared to a web platform and a decent backend). The fact remains that InDesign is meant mainly for static page designs and content - overlays do not change this in any realistic sense.
Many of my colleagues are very technically inclined (developers), as well as design savvy. Even with that level of knowledge, I just do not see them use DPS to generate apps for their classes or deploy the content through a content viewer. I certainly would never think of using DPS this way - and I teach DPS! Point in case: the Adobe Content Viewer is a far too limited viewing platform (just compare to a browser), and unsuitable for anything but testing an app.
DPS just cannot compete with the flexibility of a browser environment, which offers excellent viewing options, can display 2d and 3d content with ease (animated or not), many tools exist to leverage html5 within the browser, and so on, and so forth. My experience also tells me that most of my students tend to check out class related files on their desktop and laptops, and use their cell phones for social media and quick tidbits of information, games, etc. (many do not even touch their tablets during class time).
Integrating highly interactive "html5" content in DPS is a hassle and far less flexible compared to a web app that is integrated in a web page. And any html/css/js/svg/canvas content can be relatively easily converted to or created for either a web app which runs responsively on most platforms (either mobile or desktop), or compiled to an actual app through the use of Cordova, PhoneGap, etc.
InDesign exports to epub (zipped up html and css files) and html - which can be easily integrated in a web platform experience, with all the additional benefits that the web platform offers us educators. And it is a platform that allows for easy bidirectional communication and asset creation: students can amend the instructor's content using a variety of tools. Browsers offer a multitude of viewing possibilities, bookmarking, favourites, content management plugins, and what not, to assist students in their learning. And this is exactly what most of my students do: they use the browser as a tool to organize their content and assets. Adobe's content viewer is a joke compared. 99% of that functionality must be manually recreated by hand in an app. Madness.
The Energy 101 eBook (I would not want to call it an app(lication)) looks great, but is in effect a flip book with a bit of interactivity bolted on top of it. I am certain it took a lot of time and effort to create through DPS (heck, I built many "Multimedia CD-roms before the advent of the web), and it looks like an impressive example of what can be done with the platform, but I still remain convinced at this point that it offers little more over a printed edition in terms of usability and readability.
Throughout my years as an educator, I have witnessed many technology based educational efforts and systems, many much more focused on (e)learning compared to DPS - most failed to make even a dent in the classrooms (on any level from grade school up to university). As educators we have to be extremely careful not to fall in the "technology" trap.
Anyway, my point is that we already have an open platform with open standards which allow teachers and students to produce just about any content, interactive or not, in a collaborative environment which works on ANY device that supports a web browser. DPS is and remains, in my opinion as a teacher, communicator, and technologist, a far too static, proprietary, complicated, closed-off, and unidirectional platform for it to succeed as an educational publishing solution. And all this aside from the obscure and opaque licensing costs attached to DPS.
