Although indoor Helicopters are just toys, they use ingenious technology to produce stable flight. All spinning propellers create torque. Pilots learning to fly WWII fighters like Thunderbolts and Mustangs had to learn how to deal with the torque produced by 2000 horsepower engines and massive propellers, especially at take off under full power. Helicopter blades produce torch too. If not for the tail rotor, the helicopter body would spin under the rotors in an opposite direction at very near the same speed, rendering the aircraft un-flight worthy. Like tail rotors, counter rotating rotors cancel the torque. The Chinook is a good example of counter rotating rotors. The counter rotating rotors on these toy helicopters is one of the best techniques to counter the rotor torque. They work very well for these indoor flying toys, but they are difficult to produce and maintain for full sized helicopters. The design and function of the tail rotor is simply genius.
Finally, now that cameras have become small enough, we can have our own personal little surveillance aircraft. What fun is that?