There is a particular moment when a plane lands where it has to decrease the speed to the point of no return.

The ideal landing is when contact with the ground occurs as the forward speed is reduced to the point where there is no longer sufficient airspeed to remain aloft.

That’s the moment when a light fall occurs, the moment of losing control in order to shift from flying to sliding. Without the fall, the plane might go up again and become uncontrollable.