Well, high handle bars are for things like Bmx. (what i do)
it's high because if you had low handlebars for going of ramps and all, when you land, you're back would hurt like crazy and your hands would slip. It also makes you more feel better.
There is bmx racing but they still use bmx handlebars.
Low handlebars are better for racing (as you said)
I don't find it comfortable at all because it hurts my back a bit and i always keep my back straight. Low handle bars improve aero-dynamix.
It meens the air flows over you better so it doesnt push you back so much.
Hope i helped!
