I thought the article explained it quite well: 1) somewhat counterintuitively, in small helicopters the tail rotor can be actually louder than the main one 2)

I thought the article explained it quite well: 1) somewhat counterintuitively, in small helicopters the tail rotor can be actually louder than the main one 2) with traditional design the rear rotor HAS TO spin if the main rotor is spinning 3) with this design the rear rotor can stay still, and actually as the article points out at speed you don't have to use it as the air generates enough force on the tail to keep the helicopter straight so to speak, so the entire machine should be quiter in flight. 4) and finally yes, you can keep the rear rotor still on the ground which is safer for ground crews and quiter at the same time