I wondered myself how this would be used. Looking at the "Flyer" from the planethammock site it is clear that the PH hammocks have hooks attached to the ends of the hammock, so I guess that's the mental picture here of use. Don't know what ships with these hammocks w.r.t. the rest of the suspension, some of the other PH images show what seems to be pretty fat rope wrapped around the tree.
I'm confident HF-ers can find a use for this device. But for me, any application where I could use this I could also use a Camp Nano 23 carabiner, which is stronger than this, and if the listed 29g is for a single clip, lighter. Nano 23 costs $7 before shipping, so this clip costs less, particularly when you include shipping costs for the carabiner.