The point is not that they take their time, the point is that they spend roughly the same fixed amount of time for difficult moves (coming up with seemingly brilliant ones now and then) as trivial ones (even in positions when there's physically only one legal move). This is one of the red flags implying somebody is cheating, and doesn't even understand the position on the board. Their pace is monotonous because the time they need for copying the move over to their engine and then the engine's response is more or less constant.