From a publisher's point of view it may seem pointless to release apps into app stores that are full to bursting with apps and that are almost impossible to navigate (I stand by my view that all app stores are in dire need of a librarian to sort them out!) but unfortunately app books that are good quality are few and far between. Schools, parents and children are very keen to read wonderful tales in app form - better targeted advertising would help them find them.
The last point I'd like to make is that we are seeing these books through the somewhat jaded eyes of adults - the children that are read or themselves read these book apps invariably greatly enjoy the experience and personally I don't care if they read on paper, on a tablet, from a comic or on a mobile phone - as long as they do read - all and any reading is of value and helps to extend the imagination and give them a reading habit to comfort, amuse, delight and amaze them for the rest of their lives.