It’s literally not, that’s steam running in big picture on an inconvenient setup. No controller wake up, no rest mode, stuck with windows, no convenient app switching, need mouse/kb to do anything outside of steam. Source: have gaming PC that I never use.
Because I don’t need or want it to do any of that, nor do most people that purchase a console. I want it to be a steam-friendly PS5 replacement, and serve the exact role that a console serves. A steam-friendly replacement would have the same OS features that deck has, and allow a similar degree of customization. You are not the use case if you don’t understand that.