I found a good article from a speech by someone named Warren Ellis that really describes this better than I did:
Comics are not like film. Comics take things from film, but the two cannot be interchanged. Comics became a hybrid artform. They take things from cartoons, illustration, prose, theatre, film, music, t-shirts, posters, journalism and a dozen other things. Imagine putting twenty different animals in a blender and that the resulting horror emerged somehow alive, shrieking and wearing Star Wars underpants three sizes too small. That’s comics.
and
In a film screenplay, one page of manuscript is one minute on screen. And, on the big screen, time moves normally, and you have no control over it . Not here in comics. You can make time run so fast that the reader thinks that your comic has been injected into their eyeball, or so slow and heavy that the reader feels like you’ve boiled a doorstop novel into some condensed informational substrate.
We’re out on the fringes of the culture. We can get as weird as we like.
Sequential art creates a suspension of disbelief and pulls you into its world. Television, you have to sit there and let it do it to you. Comics are a window you step through and act behind.