Why?

[smaughazard]

Well, my kilts have no pockets, and like most of us today I carry too much stuff: keys, credit cards, drivers license, money, etc. I think it's also a good way to individualize the look. But I do favor the less ornate utilitarian styles.

[An t-Ileach]

I wear a "sporran" of various descriptions (quite often a Loewe Alpine bum-bag) because I find them convenient places to put keys, money, pens, thimbles, bluetooth earplug for the mobile phone, and so on: which, I suppose, is what they were originally.

[Archangel]

I'd go with the no pockets and separate from skirt answers. I carry a lot of stuff with me and it took a while to find the right sporran. There are many flashy, expensive, ugly (morbid) and impractical styles out there. R-Kilts was the best for my purposes.