Apparently e-trade is easy. So easy, that your eight month old child could do it. This is what Geico should have been doing from day one, not the obnoxious caveman run.
This clever commercial is not only entertaining, but it says the message in a simple way. Buying and trading stock should be easy, very easy. The concept is so creative that they never have to explicitly say that e-trade is easy, you get the idea and you remember it because the commercials are entertaining and funny.
The hook is either the creepiness nature of a child renting a clown, or how baby barf contrasts the adult nature of stock to the infant style of the commercial.