Guild Wars 2

I have hit 80 with my thief now and was thinking about builds and stuff. And then my attention was going to the number 3 weapon skill, if you have no off hand weapon. What is the purpose of these skills?

I mean you already lack the stats from an off hand weapon, now this skill is also useless like (zensored). Why is that?

During the very early leveling process when you might not have an offhand.