A spacecraft falling from infinity directly towards a celestial body accelerates until it impacts the surface at the surface escape velocity. For any celestial body, the escape velocity is proportional to the square root of 1/radius from center of mass. So dense bodies have higher surface escape velocity than less dense bodies of the same mass
This means the potential gravitational energy of an object at a given orbital radius varies with the radius of the celestial body. The surface escape velocity of all celestial bodies, independent of their mass, approaches infinity as their radius decreases towards zero. With conventional celestial bodies, this “approach to infinity” is limited by a finite radius.
The singularity of a black hole has no radius. When an object reaches the event horizon, it still has significant gravitational potential energy. How is this energy accounted for when the falling object crosses the event horizon? The object’s mass and angular momentum is added to the mass of the black hole, but what happens to the “unused” gravitational potential?