It shouldn't be. A kilt is a garment that can be worn anytime. Formal; semi-formal; smart-casual; even in the garden. The big advantage is that you only have to change the garments you wear on the upper part of your body and maybe a change of sporran (seal-skin is a bit OTT for casual wear). I have five kilts in different tartans. Oh, and the real advantage is that women can't resist exploring what I (don't) wear underneath.
Very horny, great action, pretty girl and of course the kilt. I'm Scottish, but haven't worn my 2 for years as it is essentially a special events garment.