The next episode, Storm Front, is supposed to be based on the book of the same name. They had to redo that one, why it wasn't the actual pilot shown.
Various changes were made to make it look better on tv. It wasn't feasible, for example, to use the Blue Beetle on the show because the actor, Paul Blackstone, was so tall it didn't look good visually to see him getting in and out of a beetle. And harder to film in on a tv budget where that money could be used elsewhere, like FX. They don't have the $$ of Disney to do multiple cutout beetles for filming purposes. Bob was done to make him more visual, rather than just glowing lights in a skull. The using of an actor makes him better on screen.