The SS DISengages units. That means if any of your units are engaged at the start of the turn, it will disengage them (free them up so they can act), on top of the bonus. That's awesome. If you don't know why, you've never had a copy of Shear Winds in your deck. More practically, it's insurance against all the various new ways that things can be engaged for two turns. I guess it could also be used to dodge Invisible Druid or make the life of a Night Wyvern really suck.
"Scissors are overpowered. Rock is fine." -Paper