Ever since my friend in high school (1974?) had a mount brake in his Charger and drove the car forward into the back of my brothers Torino, it hit the back of that car three times. Good thing no one was standing there. I just put a strap or a chain on any big block.
Having the torque applied to the chassis, instead of the drive train is always a good thing.
Probably not needed most times, but there you are.