Restoring a backup file is the easiest way to copy a SQL Server database to another instance. It allows you to create a copy of your production database for easier troubleshooting or debugging of an issue, to provide a copy of a database to your end users or eligible third parties, or as a light-weight business continuity/disaster recovery solution to restore functionality on another instance of SQL Server. These are just a few use cases, and the list is much longer and there are some very inventive ways of using backup-restore in the wild.
This article explains the challenges of cross-release restore to an older version of SQL engine and announces the private preview of a capability to restore a backup of a database taken from Azure SQL Managed Instance to instance of SQL Server 2022.
So much SQL Server functionality has been built with the idea of getting you from on-premises into the cloud (specifically Azure) but it’s good to see them spend some development effort on the entirely reasonable and realistic scenario that Azure is not the best choice for a company and there are many such companies still willing to throw money at Microsoft for a good product.