TL:DR; It was cheaper and they figured if it didn't work you could flip it over and try again. So it's mildly inconvenient to save a few cents on manufacturing each connector and to limited the number is conductors to 4, something it turns out was a bad idea anyway because newer USB standards use more than 4 conductors.
TL:DR; It was cheaper and they figured if it didn't work you could flip it over and try again. So it's mildly inconvenient to save a few cents on manufacturing each connector and to limited the number is conductors to 4, something it turns out was a bad idea anyway because newer USB standards use more than 4 conductors.