I am self employed as well, and the kilt is very practical indeed in the forge shop. I also prefer to think of it as simply clothing, and not costume. I don't need pockets much either, and even before I started wearing kilts I disliked stuff in my pockets, preferring a small pack and waist belt not unlike a sporran, really if you think about it.

Church and church functions are the biggest part of my "out in public" kilt wearing. Being Presbyterian, there is not much anyone can say to denigrate the wearing of a kilt in church, eh ? Of course that presumes they have read some history, which is not always a safe assumption. I guess the way I dress there could be called "costume", but really, it is just the nicest stuff I own.