chod rigs are not a new idea they were known as silt rigs in the past and were designed so that when the lead buried into silt the hook and bait didnt.The idea is to have a distance between the lead and hooklink which is short and stiff,it has excellent hooking properties.If your unsure what substrate your fishing over then its a good rig to use as your hook bait should be fishing effectivly.
A short popup straight off the lead if you know what bottom you fishing over is ok but if you in weed or silt then your rig could dissappear.You could be sitting there for hours with a rig buried