RAID is huge defense for keeping "inevitable disk failure" from turning into "massive data loss."

Do you, personally, test backup and restore of ALL of your data that you care about at acceptable loss intervals? Are you sure?

And if your acceptable loss interval is "zero," then redundant synchronous storage across devices in one form or another is all there is.

Backup is a total real-world solution to data loss like antivirus is a total real-world solution to malware and infosec.