as far as I know it the keys are sorted in a way that your fingers don't have to move so much.
The regulat keyboard qwerty was designed back in the days with the old typwriters. At that time the typwriter was not fast enough. It means it takes time to move up these metal with the letter on it.
So they needed something to slow people down so that your typewriter don't get stuck.
So they developed qwerty. There the most comen used keys are far away from each other so it slows you down because your fingers have to move all the time.
Because it is so commen it is hard to switch to a new layout. I mean it would be time, since we have 3GHz LAPTOPS which can handle a lot of char's at once
But it is just to hard to get the hole industry to use a new more effient layout.
This is like when the US tried to switch to metric system. It failed! And that's why we have so much crap in the world! To many people use it because they are used to it and they don't wnat to switch. (my opinion!)