In this video guy show the P mode brake
It's just a finger size metal stuff that hold the whole motor which this motor produce 250nm torque and car about 1500kg
When you put your gear P this little metal will hold the car for 1 year 2 years 5 years. Eventually it will have some defect.
That's why we had parking brake (hand brake).
My wife only used DSG gear for years and learned how to use it.
We never put car directly gear P and parking brake.
When we stop; my foot on brake. First gear to N then hand brake then take of my foot from brake then press brake again and gear to park.
It's doesn't matter on a flat surface but if you parking a sloped place and directly P all load will stay on this little metal finger firstly