It can get a bit humid, but then they are generally worn in a temperate climate. A Sporran, now that is f***ing genius! You can store all manner of things in there without the connotations of 'carrying a bag'.
I go to Scotland twice a year for a period of a few days. Invariably, I end up wearing kilts. So LIBERATING. I wouldn't mind wearing a kilt in the long term, but opportunities are sparse.