That is true. I guess the bat costume is just as silly as the voice.
It is. And that's all the more obvious when Batman is seen in daylight.
The thing about the voice and
the costume, is that in the first movie it contributed to the "urban legend" idea of Batman, that he was somehow more (or less) than human. The first time it's really used is when he captures Flass and hangs him upside down to get information from him. He yells at him in this awful growl, and that, coupled with the fact that Flass is being dangled several stories up makes him seem like this terrifying creature of the night. As Raas Al Ghul tells him in the first movie, "you must become more than a man in the mind of your opponent."
The moment you strip away that aspect, the moment you demystify him - and this is my problem with Batman as a character in the comics as well - then he loses 90% of his power. He's no longer scary, he's just a twat in a rubber suit with a sore throat.
I still really like Dark Knight, but there's no doubt that there are times when he seems faintly ludicrous - usually when he's not half hidden in the shadows. And Rises seems to have a few more of those scenes.