In reply to beardy mike:
You can carry half a dozen on one karabiner.
When you've placed one you don't need a quickdraw just one karabiner to clip the rope into.
So theoretically you don't need as many karabiners. Or quickdraws.
You can also pull the cord through the nut and use it as a quickdraw if you need to.
And they don't lift out as easily as wired nuts.
And you can rethread them. With fancy, colourful cord.
And they swing around like a skirt.
What's not to like?