Loading them into the Plugin allows previewing in situ with other tracks that may be in the DAW without loading them into the DAW.
I don't know if the main compatibility issues are with the Plugin it's self or the bbw4 app running in the background that it communicates with.
It would be good to see the generate code contained within the Plugin it's self this way you will get the tracks generated much quicker as they will be playing back direct from the source m4a or aiff files with no loading into ram then rendering down to wav.
This will allow the Mac version to be released at the same time as the Win as the Plugin is compiled at the same time cross-platform.

https://stash.reaper.fm/u/ReaTrak (Scripts for Biab Reaper)
Open SGU in Reaper Instantly