Page "Amiga Fast File System" Paragraph 2

OFS, the predecessor to FFS, used 24 bytes per sector for redundancy data, providing for reconstructing structural data on less reliable media.

When higher speed media ( i. e. hard disks ) became more available to the Amiga, this redundant data posed a bottleneck as all data needed to be realigned to be passed to the application.

So the redundancy was removed for FFS and the data read in from media could be passed to the application directly.