JS-1 is an inline eye hook so it is orientated either hook point up or down (at the rear) when rigged directly to a split ring - it is a straight replacement for a treble hook (up or down point is up to you, mine are up, some run them down and do ok as well)
I don't see any advantage in a swivel rigged single hook, except maybe on heavy tackle YFT gear.
The hook up rate comes from the sharpness and the recurve design, which more efficiently uses the forces involved to drive the hook home. The size of the hook also, we are replacing 4/0 trebles with 8/0 Sergeants, and it's far better to have your 25kg mack-hoo-gt attached via a big hook than a small one.
When you look at the holding and hooking power of standard treble hooks fitted to most hard bodied bluewater lures it's a joke.
Now throw braid into the mix with it's ability to shred trebles and their hooksets and singles become mandatory.
Neil