<i>Writes are limited to 1 per second, so HRD is not a good match when high usage is expected.</i><p>This is per entity group, and it's not a strict limitation, it's an expectation of performance.
<i>"Backups and redundancy are achieved via synchronous replication, snapshots, and incremental log backups."</i><p>That's nice but you can't access these backups. They are there for the system failing - not for your own needs. RAID is not a backup strategy.