My favorite point Scott McCloud makes is about how "Simplification is Amplification". In that by omitting many realistic details, you focus more on the ones left behind, allowing for them to embody more of a meaning and also allowing us, the viewer, to attach our own meanings and interpretation, effectively connecting us with the artwork or icon more. In this case the simplified imagery will embody more of an extension of ourselves, rather than a representation of reality. This allows the artist or creator to infuse larger concepts into his or her work with out limiting them to an accurate representation of whatever.
Scott talks about how we can't help but seeing a face in anything that even remotely resembles two eyes above a mouth, for instance a power outlet, front of a car, etc. So in animation, or comics, this allows the artist the freedom to recreate something that looks like a face or person, but then add other qualities or characteristics that are in no way realistic to a human being. At that point the added qualities can come with their own implications, and from the combination of these abstract qualities and the resemblance of something familiar, we can begin to make statements in regards to anything, and form concepts that could not have been represented through something closer to reality.