Question: I was just curious as to what exactly Sprite Kit Restitution actually configures? I know that it configures some behavior about an SKPhysicsBody's parameters, but how does the behavior differ?

Answer: 
A look at the description of the `restitution` property of `SKPhysicsBody` in the Apple Documentation says:

> 
> This property is used to determine how much energy the physics body
>  loses when it bounces off another object. The property must be a value
>  between 0.0 and 1.0.
> 
> 
> 

Restitution affects the 'bounciness' of a physicsBody. For instance, a node collides with a velocity of (0,-100) with the floor (for which you have defined a physicsBody). Its reaction to the collision will depend upon the resitution property. So, if restitution is set to 1.0, the velocity will become (0,100), if restitution is 0.9, velocity will become (0,90), and so on...
Restitution basically equates to an object's "bounciness"