Oh boy, you guys are obsessed with that wingtip vortex, seemingly the source of all drag. No, the reason for this wingtip shape is much simpler.
It's about the protection of the ailerons from ground contact at low level flight. This is especially important for gliders with their central wheel, but also for aircraft which maneuver a lot at low altitude. They will benefit from something that takes the impact forces and keeps the control surface intact and working, especially when this surface will be deflected downwards at the time of ground contact.
Honestly, this is the reason, not some esoteric vortex shifting.