It's mainly a visual preference to have the watch look like it's of one piece.
I like the quick micro adjusts of a bracelet to account for wrist swelling.
Also it appears that on the Vacheron website they only made rose gold case of the Malte version. One with black dial and black leather strap, the other is white dial with brown leather strap. Of the reps, only one they make that is based of the genuine which has the white dial and brown leather strap.