I used to wear one of my Fathers army kilts in the scouts on camps and such and it was fine to wear, the main problem I found was the itchiness of the wool when sitting - and no pockets! I still wear it on occasions but most of my out and about stuff has been associated with rock climbing or festivalling. I must admit the fending off drunks who are trying to look up your kilt puts me off for the latter.
My Grandfather wore one in the trenches on both the Western Front and Gallipolli and swore by them. Made the wading through mud easier, warm in winter and cool in summer (except round the waist of course - though I find it quite self-regulating) and you had an extra blanket at night. The only thing he really complained about was the pleats cutting the back of his legs when they froze. His (and my Father's) Regiment, The Queens Own Cameron Highlanders, were the last soldiers to fight in kilts in Europe, covering the retreat to Dunkirk.
Like my Grandfather I was born and bred in Barnsley so wear them if you want to they're a fine bit of kit!
A Kilt is basically a Pleated Wrap Around Skirt, Highland and Irish ones have pleats that can be 4" deep or so (to take into account the sett) and a lot of the construction and look reflects the logistics of that. Presumably the Irish plain kilts just follow the common pattern.