Play Books more closed than iBook?

This morning I installed Google Play Books on my Android device. It ‘s quite obvious that Google is trying to create its own ecosystem that will be a viable alternative to Apple, so Google Books takes its place alongside Play Music, the Store, etc…

From my first impression, I’d say that I like the graphics, the rendering of the books is excellent – even on small screen (like my Xperia Ray) –  and the possibility to read a book everywhere using the browser (unlike Apple iBooks) is appreciable. Moreover, synchronization between devices is an added value.
Among the things that I do not like, I have to mention that there is no possibility to highlight text on your mobile device (or at least I’m not finding it!), and (most annoying) it seems to me that you can’t upload your books, to be added to the library.
It ‘s the thing that leaves me more puzzled, because even Apple iBooks allows you to load books in ePub format (with no or Social DRM) in order to be addet to your library. I find this is a very a useful thing, and I am disappointed that you can not do it in Play Books (if there is, let me know, please!).
Definitively, it seems to me that you can only add books from Google Play Store.
Is Google getting more “closed” than Apple?