Women are just as good as men.

Katrin Senne was in second place after both the 8th and the 9th day of the 2018 18m World Championship in Hosin, Czech Republic (not the Women's World Championship, but the World Championship). After the 9th day she was only 5 points out of first -- 7622 vs. 7617.

She was team flying with several other JS3's, and all of them landed out the 10th day. She ended up 8th in the contest.

The reason for separate women's contests in gliding is the same as the reason you have sailing clubs for women. It is to encourage them to enter a traditionally male-dominated sport. It is the same reason you might have a male-only knitting club.