No it isn't. It's one of the most useful stats ever. Only people who don't understand what xG is say that.
xG is used to measure the quality of chances or attacking scenarios created. It's calculated using historical data and factors like shot location, distance, angle, shot type, etc.
It will tell you the approximate probability of a goal based on the quality of the chance created. An xG of 0.3 means there's a 30% chance of the goal being scored.
A higher xG doesn't necessarily mean you were the better team and dominated the game. It means you created better quality of goalscoring chances.
The numbers for the Barca Newcastle game makes perfect sense. You were the better team but they created more high quality chances on the break. Rashford's second goal was very low xG because you don't expect a player to score from there. Infact it's hardly a goalscoring chance.
Most Football fans (Game's gone brigade) tend to be tribal dinosaurs who reject any sort of modern technology, new development or statistical data driven decision making/analysis but the reason these metrics are developed is because it helps the industry massively. Data and eye test are both very important. Keep up with the times.
I believe you have misunderstood the meaning, purpose and application of xG.
@Birdy
