They also showed how the consumer/ gamer benefits from the features as well.
They didn't show off other stuff because they can always have a 2nd presentation to do that. Its an easy way to sustain interest (especially if this presentation didn't have the positive impact Google was hoping for) and just part of the general marketing cycle. After all, Sony also used 2 presentations to give out all the necessary PS4 info consumers required.
OK, true enough. Point is still, that they focused on game devs as target with this. They probably also had customers in mind, but keep more informations for later presentations.