This functionality can be used for consolidating multiple databases from several Azure SQL Managed Instances to one. If you’ve optimized your workload over time and don’t need multiple instances, with this you can easily consolidate and save cost.
If you’re hosting multiple databases that might serve different needs or different tenants, and you have a noisy neighbor situation, you can use this functionality to move a database to another Azure SQL Managed Instance to wither contain the problem or provide more free resources for the busy database.
Promoting databases from test to production environment and vice versa, is another typical use case for database copy and move. With this, you can copy your production database to a test environment to comfortably investigate that query whose performance degraded recently.
These are a few scenarios, and I’m sure you will be able to find many more useful applications for database copy and move.