Did you read the article to the end? It does bring speed ups for high resolution, like 4K. It's at more conventional laptop display sizes that its roughly on-par with, but the GPU scales better with pixel count.
Only on Linux it seems. The fact that it makes rendering slower on lower resolution is a big concern.
I’m all for speeding up Emacs as a long time user, but I share emacs maintainers stance on not accepting llm code.