Well, I think it's good to have vectorable work in vector format. The Jungle King marquee is one that will not radically benefit from being in vector format however, other than being able to be blown up to a huge size (which isn't very important like you mention)
If there was an easy way to simulate halftonining in Illustrator I'd be more apt to think images like these could be accurately traced. As is, I'm inclined to agree that this image just needs a good / clean scan.