A high quality grinder also minimally heats the beans as they grind - heat can change the volatility of the oils, resulting in changed flavor (and usually not for the better)
Correct, this is why people prefer burr mill grinders made of ceramic instead of metal since ceramic is more thermally insulating.
This isn't true in the high-end coffee community. No one uses ceramic burrs, and they are generally considered to produce worse coffee than other burrs.