Why would you say that ? just chill we are here to discuss these things here. The shift key is used when you wish to move gear lever from P mode to N or any other gear without starting the car. As you know you cant move gear lever from P mode without starting a car and pushing brake pedal.
For example your car is broken down and needs to tow a car. you cant tow a car in P mode because in P mode your car wheels are locked. to unlock the wheels first move it from to P mode. There you press the shift lock button and your gear lever will free to move.