The article explains it. This is not for streaming over the web, but for editing professional grade video on consumer hardware.

davinci resolve is the only commercial NLE with any kind of vulkan support, and it is experimental

prores decodes faster than realtime single threaded on a decade old CPU too

it doesn't make sense. it's much different with say, a video game, where a texture will be loaded once into VRAM, and then yes, all the work will be done on the GPU. a video will have CPU IO every frame, you are still doing a ton of CPU work. i don't know why people are talking about power efficiency, in a pro editing context, your CPU will be very, very busy with these IO threads, including and especially in ffmpeg with hardware encoding/decoding nonetheless. it doesn't look anything like a video game workload which is what this stack is designed for.