Thanks for your inquiry.
We started providing our tool for converting documents to EPUB separately from MS Word as there were simply too many restrictions when it was integrated with MS Word. For example, there was no way to supply additional options to control how the EPUB is produced. Not everyone could use it if they did not have a copy of Office, and it was not working for Word 2010 etc.
Therefore we made it into a standalone application. It should not be any extra hassle to use this separately from MS Word. For example, you can just point to the file path of your document on disk and convert it with one button (even when the document is still opened in MS Word).
Please let us know if we can help you with anything else.