It read the temp

Nah seriusly, it makes sure that if the temps get over 69 degrees, because if it does it will retard the ignition and you will loose power. Kind of a safety device. That is why you (should) fit a better intercooler so the temp's never get that high... and with lower temp's come more bhp.
And that's because cold air takes up less space than warm air. And the more air you can get in chamber the more fuel you get in and = more bhp.

Correct me if im wrong people.