I guess this question brushes along the lines of why "real Japanese" can't be learnt from drama/アニメ. I was watching the Dark Knight (2008) with Japanese subtitles and I noticed that the translations sounded like they were sentences written only used in a book/literature and not actual conversational Japanese. For example, there's a scene with the Joker in which he says
Joker: You see, in their last moments, people show you who they really are.
To which it was translated as
Joker: あれだな、末期においてな、本性を 晒け出すもんだ。
After consulting with my Japanese friends about how you would translate this to conversational Japanese, it just got me wondering, why are movie translations in Japanese done like this? I.e is it just for effect? Of course it depends on the era/setting but this is a modern film. What would be the difference/effect if conversational Japanese was used instead? i.e