DRM (if any) is one difference. Circumventing copyright controls can open you up to civil and criminal penalties.
Not all digital books are DRM protected. I recently listened to Cory Doctorow’s audiobook The Bezzel and at the end he tells you that you have the right to loan or sell your copy of the audiobook.
Not all digital books are DRM protected. I recently listened to Cory Doctorow’s audiobook The Bezzel and at the end he tells you that you have the right to loan or sell your copy of the audiobook.