I prefer the model where my kids can get stories read to them by anyone.
Also I think you could have a hit with moms if you do an autoplay feature. Moms need 30 mins of time to get something done. Moms dont like it when their kids watch TV. Your app should allow a Mom to click play and then deliver 30 mins of books to the child, uninterrupted. IMHO if it's a high quality experience moms would pay for this.