IO has a tangential benefit as well when it comes to recovery. For some large disk drive raids (1tb+) the rebuild time has gotten so large that even with an available hot spare you have a considerable exposure window during a rebuild. I believe this is what helped drive the push of RAID 6 over RAID5. In theory you still had 1 disk of protection during a rebuild. Although SSD's are primarily champions ins random IO and not the linear read/write of a rebuild they still have the potential to reduce this window of risk.