For me its all about proportion. A standard length jacket obscures all those amazing pleats and creates an awkward conflict of shapes. It also seems to make a person look rather shorter and frumpier. A high waisted kilt and matching jacket gives the appearance of longer legs and a shorter torso - a shape that suggests a more youthful profile.

BTW the kilt suit worn by Brian Cox looks like one of Howie Nicholsby's creations from 21st century kilts. In fact I think Howie was wearing that very style kilt suit the first time I met him - and yes he looked much better in it than Brian...