What are benefits of unloaded wingtips? What are aerodynamics benefits of using unloaded wingtips (zero lift)? does unloaded wingtip make inner parts of wing more efficient?
(I know that unloaded wingtip reduces bending moment,so structural weight can be  lower, thus reduction in L/D and higher net wing lift (lift minus wing weight), but you can connect wingtip with wire and use elliptical distribution..so..)
Twofold (at least): firstly it results in less energy going into the tip vortices, secondly, is the reduction in lift is gradual towards the wingtip then it tends to reduce the spin tendency - the angle of attack of the tip is typically lower than at the root and so it will stall later than the root.  In a slow-flying aircraft such as a paraglider the airspeed may be significantly lower at the tip when turning, and so the angle of attack for a given sink rate will be higher, increasing the risk of a spin.