It's so people can reset their w/l, and their k/d. It would be an extra feature, after you achieve the required stats.

Would give me incentive to play more. "Finally an appropriate ratio..."
Removes the point of selective sparring, and making new accounts just for some good stats.

Idk if it's just me, but when I am bored in a game I like to start over and see how much better I can do. Since this is graal, and your items would be lost, a NG+/Reset would be nice. If my total kills, deaths, wins, losses, bks, hours could be kept somewhere else, then that would be great. If not, I'd still want to start a NG+

I figure it would also be a great addition for when they update the guild system.