Where did I say it was?

Also it could well be, but it would be for the wrong reasons, I,e if it was running a tad lean for whatever reason, with no closed loop to correct it, you would save fuel

The most important part of closed loop fueling is to know that where ever possible the engine will be running the correct AFR for the condition, and know it is not running lean/rich, and to ensure engine longevity is maintained due to the mentioned points.