Ginnel
Explorer
Not only that, but the +1 to damage is only for the main weapon.
However, there are other advantages:
1) Two Weapon Fighting is a prereq for Two Weapon Defense. +1 to AC and Reflex is nice, especially considering that it is a shield bonus, so Armor Specialization stacks with the AC part of it and Lightning Reflexes (or Combat Anticipation) stacks with the Reflex part of it.
This is quite neat actually I hadn't looked at it like this before.
Wielding a longsword in Two hands gives you one more damage with a light shield you also get an AC bonus of 1
With a couple of feats you get the advantage of two handed wielding a longsword (- it being a two handed weapon for reaping strike and two handed weapon prof for a fighter) and the benefits or a light shield this is infact neat, you also get this "versatile" bonus for any weapon not just versatile ones.
It does seem a bit odd that this bonus for damage and the actual versatile doesn't scale to 2 then 3 with tiers, or even just to 2 at 21st when all attacks will be at least 2 weapon damage