Further to AEUENG's comment, the pressure 'bump'/surge occurs as you push the lower rear mounted outflow valve towards the runway surface on rotate, which sits in the underwing higher pressure airflow, amongst other effects.
The standby mode now-a-days is just what we used to use day in and day out, back when pressurization was a novelty. a.k.a Viscount fun times. You had to think then, and the ability to think 'how high am I? _what has to happen to the valve to make the cabin pressure increase and so make us/the cabin go 'down' ' was a definite benefit.