Certain atties require it in their build. The GG atties (and their clones) like the Odysseus (nautilus/terminator), Penelope (euphoria), Ithaka (Hercules), to name a few, all require non-resistant coil legs to travel down the sides of the atties internals to make contact at the base. Also the eBarron dripper and Killer use it as well, but it's not quite as necessary for those. Most regular drippers,
tanks, and genisis atties don't use it at all.