Yes, to me it does, FlorenceArt.

As you surely realise, you can also purchase a book and read it in Marvin; it will just no longer be DRM-protected at that point. The reading experience offered by iBooks is
abysmal, and I wouldn't be willing to put up with it even if I was purchasing books from Apple (but I use other online stores).
You might find it interesting to look at the following thread in Marvin's GitHub:
https://github.com/kguil/Marvin-Roadmap/issues/159