Yes, it evidently needs a little bit of converting. The XML parser used for the Mac version is not as good, so the XML files need to be adjusted (standard practice for getting mods to work on a Mac). There might also be a few Python issues since the Mac version of BtS uses a slightly older version of Python.
What FerF needs the most to get it working on the Mac is someone with experience doing mods on a Mac to give it the necessary adjustments. It does include a rather detailed change log in the changes.txt file.
For the Mac, the extra content would be nice but the main benefit is probably getting all the bugfixes for FF that it has (everything up to its release date from the official FF thread should be in there plus a couple more, as I recall).