I believe that a backup strategy should protect you from hardware failure, file erasure and corruption, and disasters. A raid array does protect you from a drive failure but it does not protect you if you accidentally erase files or if folders become corrupt. If you use RAID storage you still should have another backup. I also think you need some type of off site backup, something that will still be available if your work space is hit by some type of disaster. The Marshall fire in Colorado in 2021 is a reminder of how quickly homes can be destroyed.