Panel Self Refresh should largely just work, and I believe has been on laptops for a long long time. Here's Intel demo'ing it in 2011. https://www.theregister.com/2011/09/14/intel_demos_panel_sel...
I'm not sure that there's really anything new here? 1Hz might be lower. Adoption might be not that good. But this might just be iteration on something that many folks have just not really taken good advantage of till now. There's perhaps signficiant display tech advancements to get the Hz low, without having significant G-Sync style screen-buffers to support it.
One factor that might be interesting, I don't know if there's a partial refresh anywhere. Having something moving on the screen but everything else stable would be neat to optimize for. I often have a video going in part of a screen. But that doesn't mean the whole screen needs to redraw.
Probably patent licensing shenanigans kept it holed up for awhile.
I’m not an expert here, but …
CRTs needed to be refreshed to keep the phosphors glowing. But all screens are now digital: why is there a refresh rate at all?
Can’t we memory-map the actual hardware bits behind each pixel and just draw directly (using PCIe or whatever)?