As is the genetic difference between a St Bernard, a border collie, a pit bull, and a chihuahua. Yet those small differences do create some significant differences in appearance and behavior between the various breeds of dog.
With dogs those traits were selected for by humans, the differences held as each strain was held to a standard and the bloodlines kept separate.
Humans had different environments selecting those traits, and different sexual selection criteria.
The number one difference between human populations is cultural, not genetic.
There is vanishingly small genetic differences and most of those have to do with local climate adaptation.
Being better at dumping heat may make for (all other things being equal) a better athlete - but there is in biology - as with economics - no such thing as a free lunch. Every trait has a optimal range, a cost benefit trade-off, etc, etc.
Differences do not mean that one is better and one is worse - they mean that one is better is some situations and others are better in other situations.