OS handles are needed if your bar has a mini-5th line. If the wind picks up quickly and you need to self land, you need a way to be sure you're not going to get lofted on land.
If you have a full fifth line though, I don't think you need it.
Ever had a 5th line jam or break? What's your backup plan then? Ditch the kite? I prefer other options. Like if the kite rolls and 5th wraps it, release the 5th and switch leash to OSH, ride to beach with some safety...
I don't think the single rear line is any better than the single fifth line.
OSH is not better than 5th or mini-5th, it's a smart backup.
If you have used both, you know, mini-5th or 5th is more convenient, faster to reboot, and more controlled. OSH is usually just a backup system.
What's the benefit of an OS handle over a fifth line?They both would get tangled just as quickly from a kite looping multiple times.
Maybe, but at least the outside line is outside the twist, while fronts and fifth are locked in the middle.
If you let a kite spiral too many times, you are going to have to let it go regardless of the safety system.
This will tend to happen when there is a bridle failure at the kite.
If the problem is at the bar end, or with a 5th line, going to the OSH can help by slowing if not stopping the loops so the kite will crash and stabilize on the water.
Kites trying to loop around the outside lines make bigger loops and usually crash quickly with less relaunch risk.
Even if the kite keeps trying to kill you, crashing it with the OSH may buy a few seconds to breathe and release your leash.
Best strategy is to pull the safety before deathlooping starts, and switch to OSH backup before the kite makes multiple loops. Too many loops = best to ditch it all.