It shouldn't be safer. However, using a battery-backed write cache in hardware RAID allows the OS to just dump the writes into the cache, get the message that t

It shouldn't be safer. However, using a battery-backed write cache in hardware RAID allows the OS to just dump the writes into the cache, get the message that they're safe very quickly, and then move on to the next thing. So, a battery-backed write cache allows it to be faster while still being safe. You can still get the same level of safety without it, and you can get very close to the same speed by switching off all the protections (don't do that), or by logging writes to a separate fast storage device (like a SSD or a battery-backed RAM).