As I've said many times, it is a load of bollocks because IT'S NOT WHAT THE STAT IS MEANT FOR.
xG was designed to be an improvement on just having the number of shots/shots on target to show how well you've played in attack, that's it. Over long periods there is often a degree of of correlation between xG and how many goals are scored, much like there is a correlation between shots and goals but tables like that are utter nonsense.
Specifically to the Rogers chance mentioned, all xG uses for it's calculation is distance from goal, angle, ball height and shot type. So Rogers had a shot from fairly central, about 4 yards out with his left foot and the ball was very low to the ground, with no more context you'd expect that chance to be scored most of the time.
