I use a thinner one for my reef hold-off rod. I don't really know what to call that thing, but it's a 14" aluminum rod with a small handle that I jam in the sand to steady myself during macro photo, or wedge in a crevice in the coral to shoot without hurting myself or the coral formation.
Anyway, between balancing the camera and holding myself in position, this keeps me from losing it until I stow it away on the swim to the next place of interest. And the coil allows me to grab it and stretch my arm out to whatever position I need to brace my body from.
The one in your pic is probably too light for my cameras, and a little too heavy for my poker. What is that thing called, anyway?