So do story formats matter? To a certain extent no. The important thing is getting the story across. I'm an avid reader but not all of my family are and some prefer audio books. To my mind, they are still "getting" the story, albeit in a different form than the one I'm using. Books, of course, are of vital importance (which is why I said only to a certain extent, no). They are part of our heritage, print is special and it would be difficult to portray poetry in a film! You can read books whenever it is convenient for you to do so and in a wider variety of places, something a movie would find hard to match!
And from a fairytale viewpoint, while I have no problem with Disney bringing fairytales to life, you really should read the original versions. Disney really couldn't have portrayed the real version of The Little Mermaid as Hans Christen Andersen wrote it as that would've needed a much higher cinema certificate than the audience it usually caters for! And there are so many fairytales that have not been/are unlikely to be adapted. Given fairytales can be pretty blunt about the horrific fate usually reserved for its villains, Disney would have real problems here in staying true to the story.