|easy to use
When I first started fishing with a fly rod, I spent a lot of time tying compex knots to join the different part of the rig. I wish someone had told me about loops when I started, because they would have saved me a lot af pain and frustration. I do not think that loops are the best way to join two parts of the fly line set up, but they sure are easy to use, and until you are really competent with a flyrod, you'll be pleased to know that a leader can be changed in a jiffy, without tying any knots. The loop-to-loop connection makes it so much easier to change that windknotted leader or have several fly lines that has to go on one reel.
As you become a better fly angler and more confident with knots, you can always return to knotted connections, which in some cases can give better performance than loops.
The loose loops can be bought, but they are very easy to make yourself. An other prossibility is to make the loop directly on the flyline which results in much less bulk and a much stroger connection.
How Juro Mukai sets up his shooting head system.