I was hoping that you'd get an informed response, so I left off answering for a while. Since no one else answered, here's my two cents: (also, many people won't answer a question, but they'll jump right in if a wrong answer is given
When I last checked about a year ago, DarkHorse only sold "app" versions of their books which would require a desktop or tablet to read. I guess ADE-style DRM doesn't work with CBR/CBZ files. I read somewhere (maybe here on MR) that this was common practice in the industry. I left in disgust and haven't gone back since, so I don't know if they've changed anything since then.