Then again, Stadia's streaming performance and graphical capabilities were subpar compared to established competing services like GeForce Now, Xcloud, and ShadowPC. If it were better it might have been worth it.
Meanwhile, your XCloud stream is hosted by an equivalent of an Xbox Series X, which while a console-level experience, the games were shinier and prettier than Stadia.
And otherwise I've found their streaming quality, performance, and latency, to be about equal (not the best) although XCloud continues to improve to this day.