Why do a lot of animation videos have wiggly lines? You see this style often in animated videos, e.g. this one: 


                
            

The outer borders/lines of the elements sort of wiggle (for want of a better word) at a high frequency, giving the video more overall movement/activity. Of course for traditional animation that is drawn frame by frame, this is a byproduct of the illustrator drawing the shapes a bit differently every time. However, the video I linked above rather looks like most of it's elements were animated in After Effects (or similar software) rather than being hand-drawn frame by frame. 

I see this style quite often, I would like to know if this most likely an intentional effect (for example to give the impression of a hand-drawn animation) or the byproduct of a digital animation method. Also, is there an easy way to replicate this effect in After Effects without having to draw every frame (or manually transform the paths of my vector elements every frame)?
This seems to typically be called 'Squigglevision', it's even patented. There do seem do be ways to replicate this in After Effects.