Major Description
Windows comes up with a feature in the kernel called RegBack which is extremely helpful alongside transactional registry logs to strengthen up the Registry integrity in case it gets tampered due to corruption or factors like power outages during a registry write.
The alternate hives mechamism (which is used by the SYSTEM hive only) we have isn't super effective against all corruptions, apart from other kind of corruptions like FS ones of which there's nothing the CM module can do in this case.
RegBack will aim to deprecate the alternate hives support in the kernel for good.