...or in the case of Rob Roys, without corners?

I don't own a sporran proper, relying mostly on the canvas pouch that comes with my AKs. Occasionally I use a leather bag when I feel a little more dressy.

Yesterday I was doing a little more walking than usual while wearing the leather 'non-sporran' and I could distinctly feel the corners poking the inside of my thighs when walking. It didn't leave a mark or anything but was definitely annoying.

Is this why traditional sporrans are rounded in shape at the bottom?