The eBook file format transform is a very common requirement in our daily life. For example, many friends will google for "how to let Kindle read ePub files". In fact, the better solution is to convert ePub files into Azw3 or mobi files which are supported by Kindle.
There are also some requirements, such as wanting to print files in mobi format, but some user can't even open mobi on their smart phones. At this point you can convert the mobi file into a docx or pdf file and open it with the appropriate reader to print out.