The SOUND that comes from the WINDMILL style( like an airplane propeller) is totally eliminated when using an airfoil (the blades) that is mounted vertically. Also, bats and birds can 'see' the helix style whereas the the propeller blade style is 'invisible'.
These HELIX designed systems take up a minimum of ground space, do not need braking to keep them from tearing apart, and pretty cheap (compared to the giant propeller type blades on the large 'turbines').
Instead of us buying the giant windmills from CHINA and buying the electricity from the utility, we could have multiple HELIX style systems set up on our properties. City buildings could have dozens of them mounted on the roof. No one would even see them. And it's usually WINDY on the roof of large buildings.
The reason our nation went with the WINDMILL style is because our corrupt politicians made deals with the CHINESE to get kickbacks from the sale of those windmills.