"And gaming is a usage from the beginning that is all about interactivity, it's all about low latency, it's all about what a gamer expects. You push a button, you click the mouse button, you push a key, and you expect something to happen immediately on the screen. Right? And because of that, you're going to need most of that to happen as close to the workload as humanly possible."
"Now, there are some games where you don't need that. But for the vast majority of games, I think you need that."
that's the crux, it's about input lag. Building a PC is cool and all but most people do that once every few years or so, with perhaps some tinkering in between. Input lag though, that's something you deal with every single time you play a game