Exchange Decommissioning Set-Remotemailbox command

Hi all,

I have a situation where someone was with a hybrid Exchange Server configuration was using scripts to provision accounts with Set-RemoteMailbox. Testing was being done with the recipient management using the exchange management and noticed mailboxes are being provisioned and working as expected without even running their set-remotemailbox commands and are curious if this is even needed anymore.

So I guess my question is, at this stage where .\CleanupActiveDirectoryEMT.ps1 is the last thing to do, would set-remotemailbox still be necessary, and what would it be used for. I know usually you can just create an on-prem mailbox, synced and license, so I'm not sure if set-remotemailbox is required for new mailboxes or but I'm thinking it's for managing mailboxes that were previously migrated.

Thanks for any input.