The Mystery of Air Conditioning

Is there a technical reason for why the air conditioning in most buildings seems to be set to “FREEZING”?  I mean what is wrong with say 78 degrees? Does it really have to be 65 or below inside when it is 85 or 90+ outside?  In our home I always try to run the AC to remove humidity and provide an acceptable temperature level but not to turn the place into a meatlocker.  I wonder how significant a dent in peak electricity consumption could be achieved by more moderate air conditioning.  Would seem to be meaningful.