Bent up wings on Schempp-Hirth and Jonkers glider

Can an aerodynamicists explain the reasoning behind the bent up wing tips of the Schempp-Hirth and Jonkers gliders. I thought Schempp first started this on the Nimbus4 purely to keep the outboard tips from getting scraped, but now the tips are bent on shorter wing birds. Someone fairly knowledgeable once told me the the bent tips actually hurt performance in the run but help in climb. I just wanted to get a bt more educated not the reasoning. I noticed the Quintus has bent tips but the same wing on the Antares 23 were straight.