There are two use-cases. Already sitting at a PC and you just pop your headset on - your idea makes sense. But traditional VR means standing up in a dedicated space (2m x 2m) and demands uninterrupted time. That's a high friction activity, and adding setting up a PC and Oculus Link and Steam VR before you start playing makes that friction even higher to the point where it's a niche hobby. Most casual players are doing stuff like VRChat and Beat Saber which can run on low powered hardware, so having a basic game-playing ability is a good idea.