One of the foundational changes that are happening as part of this effort is that Windows 12 will feature state separation. This essentially means that different components of the OS will be broken up into different partitions, many of which aren't user accessible. This is something that's fairly common for modern operating systems, such as Android and iOS, and it has a few key benefits. The most notable one would be faster updates; since most of the system files are in partitions that can't be accessed by the user, it becomes easier for system files to be updated without interrupting usage of the device, making for a faster and more seamless process. It can also improve the reliability of the reset procedure on a device, so you have a more consistent experience when you want to start fresh.

New state separation system
Although it’s unclear the actual features and changes that will become part of the new version, recent reports suggest that the company will be partitioning the operating system into different modules with a project known as “CorePC.” This new approach will allow the creation of different editions of Windows 12, depending on the requirements of the device, since not every form factor can offer the same features and capabilities, such as legacy support for Win32 programs.

“CorePC” will also introduce the concept of “state separation,” which is an approach that will divide the entire system into several “read-only partitions” not accessible by the user or third-party apps. In contrast, Windows historically has been using one partition for the entire installation (not counting the boot and recovery partitions), which means that system files, applications, and user data are stored in a single place. The benefit of separating the components into different partitions allows better management with faster updates while improving the platform’s security. Also, this approach could make resetting a device faster and more reliable.
Source, Pic Techsupport