In that Reddit AMA with Gary Illyes, Gary said out right and clear that the theories around Google using UX and behavioral signals such as CTR and dwell time are "generally made up crap." He added "Search is much more simple than people think."
He also took a jab at Moz's founder, Rand Fishkin, who has often produced studies claiming Google uses these types of metrics for ranking. Gary Illyes wrote "Dwell time, CTR, whatever Fishkin's new theory is, those are generally made up crap."
I know most of you don't believe it but Gary, although very sarcastic, is a straight shooter and wouldn't out right say something like this if he didn't believe it to be true.
Google has said for over a decade that these metrics are not used by Google because they are easily spammable and very noisy. Google's messaging around this has been consistent and clear for well over a decade.
Forum discussion at Reddit.
