Warning, the sound of a broken record coming up...

> An unreliable backup solution.

Nope. RAID is not a backup solution. It provides redundancy so the array can survive an event like a device failure (and so the data survives as a consequence) without significant downtime for repair (with zero downtime if you have hot-swap hardware) but it does not, and is not intended to, protect the data from the huge list of other things that can affect it.

RAID is redundancy for reliability purporses, not backup purposes.