The multiple loops are not for gravity assist (or gravitational slingshot [0]) as I had initially thought. It is for the Oberth Effect [1], which I only got to know of today.
From the Wikipedia article -
>> Oberth maneuver, is a maneuver in which a spacecraft falls into a gravitational well, and then accelerates when its fall reaches maximum speed. The resulting maneuver is a more efficient way to gain kinetic energy than applying the same impulse outside of a gravitational well.
>> In some cases, it is even worth spending fuel on slowing the spacecraft into a gravity well to take advantage of the efficiencies of the Oberth effect.
Fascinating! To say the least!