Well that's a good question. It comes from my interest in digital preservation and archiving, which might at first seem a little odd given all the effort ensuring that the digitised copy, image or whatever is as accurate as possible, and as least likely to change as possible. Reformattable free flow formats such as epub definitely do not measure up against these requirements.
But people tend to forget two things - firstly what we are creating is digital copy of the cultural patrimony of the society concerned - ie the books, the stories, the literature, the songs, the poems that all go together to make a culture - and secondly one of the aims to promote access - this is why we spend all this time when we build systems to make sure that people, ie ordinary people off the street, can access the material.
Access is not just for scholars. And when we are digitising to preserve content this is doubly so.
I was especially struck by this when I worked at AIATSIS. One of the things happening there was to digitise tape recordings of Australian Aboriginal language, story telling, music and chants. These tape recordings were possibly the only copies of in existence, and the tapes were degrading and rotting. Given that Aboriginal societies were pre-literate this was doubly important. However what we were preserving was not just for use by linguists and anthropologists, but also by the people from that particular group, so that they could pass on and refresh their memories of the old stories and songs, digital cultural repatriation if you like, and also in a society without books or photographs, and with prohibitions on displaying images of those who have passed on, develop a connection with the past by hearing someone identifiable as their grandfather or uncle speak.
And for these purposes, a CD or an MP3 recording was good enough. They didn't care about preservation formats or the like, all they cared was that the data was safe and they could get another copy if their $35 no name mp3 player broke.
So yes, preservation was important, but only as a means to guaranteeing reliable and repeatable access and dissemination.
So e-readers. When we digitise books we can either digitise the content or the appearance or both. In the case of handwritten books there is clearly an advantage in doing both, if only to allow amusing discussion of the roles played by monkeys in medieval scriptoria. Printed books, well, but then OCR is cheap these days.
And that's fine for preserving content, but not access. Now wierdos like me might want to occasionally read texts such as William Fowler's translation into Scots for James VI of Machiavelli's The Prince - the implication being that James VI couldn't read Italian - because we're interested in history, language and our cultural heritage, and like twisting our brains doing translations. However to do this we don't need a photographically accurate copy of the text, we just need the text, either as an epub or fed through something like an espresso book machine to provide a one off printed copy.
And while it might at first sight look like scholarship it isn't - it's allowing access for all sorts of reasons, cultural, artistic etc.
Like art galleries it's about access. It doesn't matter if you visit them to get out of the rain, to pose as an intellectual, or are deeply interested in impressionism - it's about access pure and simple.