When wading the flats using your hand for fly line looping can lead to many lost shots trying to untangle your line. When you loop up your line in your hand multiple times at once like in this picture above you are asking for a mess. These loops will cross into each other. When this happens, as you start to cast one loop will come tight around another and bam you have a knot. If you have more than one loop crossed you can end up with a huge mess that might take you quite a while to get undone.
I would recommend just dragging your fly line behind you while you wade. No loops. Then the line is always straight and will not tangle anywhere near as easy. Remember, no fly line looping, let it drag!