And the reason it's better is because it's easier to relate to.
You have a hero, with NO POWERS, able to stand up to other villains, etc., using nothing but himself, his wits, and his gadgets. And it's easier for humans (yes, generalization, shutup) to relate to him because he's human; essentially, more like us than Superman, Spiderman, etc.
It's the same thing with Ironman, to a degree. Ironman is Marvel's Batman (to me) because he meets relatively the same criteria (wits, genius level, vanilla human. ****in' rich). Except he's outted himself as Ironman, and the public knows. Obviously with the Bat, that's not the case.
/rant