To combat threats specifically targeted at the firmware and operating system levels, we’re announcing a new initiative we’ve been working on with partners to design what we call Secured-core PCs. These devices, created in partnership with our PC manufacturing and silicon partners, meet a specific set of device requirements that apply the security best practices of isolation and minimal trust to the firmware layer, or the device core, that underpins the Windows operating system.

Using new hardware capabilities from AMD, Intel, and Qualcomm, Windows 10 now implements System Guard Secure Launch as a key Secured-core PC device requirement to protect the boot process from firmware attacks. System Guard uses the Dynamic Root of Trust for Measurement (DRTM) capabilities that are built into the latest silicon from AMD, Intel, and Qualcomm to enable the system to leverage firmware to start the hardware and then shortly after re-initialize the system into a trusted state by using the OS boot loader and processor capabilities to send the system down a well-known and verifiable code path. This mechanism helps limit the trust assigned to firmware and provides powerful mitigation against cutting-edge, targeted threats against firmware.

https://www.microsoft.com/security/blog/2019/10/21/microsoft-and-partners-design-new-device-security-requirements-to-protect-against-targeted-firmware-attacks/

If you think a little it is some type of extension of Intel Boot Guard to more platforms, as it will require to have special one time key writing to CPUs.

Most probably real goal is to test in on specific markets first before making it wide feature. Real goal is same as with Intel thing - to prevent devices repair. Microsoft has direct interest here as with each new device sold they get nice money.