Hi,
i am the maintainer of the libburnia libraries.
I am not aware that Brasero uses extra functionality when having them as backend. Nevertheless they offer the opportunity to do ISO 9660 production and media burning by a completely different implementation of the backend. This may help to distinguish Brasero bugs from backend bugs.
libburn may replace cdrecord resp. wodim as burn backend for CDs and growisofs as burn backend for DVD. Afaik the capabilities of growisofs and libburn about BD media are not used by Brasero.
libisofs may replace mkisofs/genisoimage as ISO 9660 producer.
Brasero does not use libisoburn (although that would give it interesting xorriso features for backup and bootable ISOs).
A disadvantage of libisofs is that it does not create UDF filesystems for DVD video players.
A disadvantage of wodim and genisoimage is that their package cdrkit is not maintained any more. Even the home page of cdrkit has vanished. (Debian still has a source tarball.)
cdrecord and mkisofs are still actively developed. Their problem is more in the fact that its developer has peculiar ideas about proper social interaction.
growisofs is just fine with DVD. It has a little flaw with not yet formatted BD-R, though. Regrettably it is not maintained any more. (I can help fixing bugs.)
Have a nice day
Thomas