There are at least two advantages
1. You never have to switch application but work all the time in the word
processor
2. There is only one file, not an unformatted and a formatted one. At least
I sometimes got confused, and if a manuscript was rejected, it happens even
to me, it was difficult to reformat. Any changes made directly into the
formatted manuscript had to be transferred to the unformatted one.
The only disadvantage I can see with the plug in module is that it only
works with Word 5 and 6