Frank Miller ~ the Joker goes on the David Letterman Show. In the comics it is David Endochrine. But, come on.
This scene is important as a storytelling concept:
The written word in Western Culture is read left to right. This is not news. It is so obvious people do not even mention it, actually. In comics, you will often see the action subtley leading you to read left to right, top to bottom, without stopping. Frank Miller, in particular, is a master of the cinematic style of comics. Especially in DKR, where Miller’s pacing is frantic and without respite. And then, all of a sudden, the Joker returns. He pulls back the curtain and stares at the talking heads. Echoing the talking heads that litter the pages before. Joker pulls back that curtain and casts judgement and death on all of it. That storytelling element is why this is the best villain entrance I can think of.