I'm not a graphic designer so I can't speak to why this works, but it's pretty neat. I think in the case of Batman it's mostly just luck/coincidence that

I'm not a graphic designer so I can't speak to why this works, but it's pretty neat. I think in the case of Batman it's mostly just luck/coincidence that it works. The logo isn't designed by professional designers/marketers who are carefully trying to craft a certain response. It's literally just whoever happens to be drawing Batman at the time draws the logo on his chest in whatever way he desires. Kane (who invented Batman in the late 30's) wasn't a designer or marketer in the slightest. He just decided to throw a black bat on Batman's chest. I suppose in the case of the movies the logo is carefully pondered, but most of these variations came from the comics themselves.