Keeping a cloned drive is a useful method to recover from Mac failures quickly.
Using a cloned backup drive and Migration Assistant, Jason Snell was able to restore his Mac to the same state it was in before the failure.
With the APFS filesystem, tools like Carbon Copy Cloner can store previous versions of your disk on the backup drive, providing extra layers of data protection.
Although the restoration process using Migration Assistant can be slow, keeping data files on separate drives can help expedite the recovery.