Bodies in circular orbits are rare because they are sensitive to the gravitational effects of other objects.
Rather than going into the mathematics and being accused of engaging in "technobabble" here is a simple analogy.
An old party trick is to balance a chair on one leg. While it is difficult it is possible. From a physics viewpoint, the balanced chair is said to be in a state of "unstable equilibrium". The slightest nudge and the balance is destroyed and the chair either topples over or ends up resting on four legs.
If you apply the same nudge to a chair resting on four legs, it might rock about but ends up in its original configuration.
An object in a circular orbit is like the chair balanced on one leg. If you apply a perturbation the orbit is destroyed (chair topples over) or it ends up in closed elliptical orbit (chair rests on four legs).
The elliptical orbit on the other hand is far more stable to perturbations.
Incidentally the chap in the video who is confused about relating the dimensionality of space to the strength of gravity at least got the marble analogy in the bowl right, it applies to both orbits and chairs.
Regards
Steven