I think it's a question of write vs. rewrite. Most archival backups are write-once in the sense that they're append-only, especially now that storage is so che

I think it's a question of write vs. rewrite. Most archival backups are write-once in the sense that they're append-only, especially now that storage is so cheap nowadays (see: Amazon Glacier). SMR performs generally fine except in the physical rewrite case. A 6TB disk is unlikely to see a lot of physical rewrites except in this pathological case of a RAID rebuild that people are complaining about.