We have been through this before.
Sherman takes the right handed quarterback's right side.
Given that teams typically put their best pass blocker at left tackle the Seattle defensive scheme does the following:
1) Encourages the right handed quarterback to throw across his body to the left leading to greater inaccuracy, longer flight time, and poorer vision....all allowing Earl Thomas opportunities to make plays on the ball.
2) Isolates Cliff Avril on the typically lesser pass blocker (right offensive tackle) for the newly created "blind side" (QB looking to his left to avoid Sherman). Avril is as adept at stripping the ball as anyone.
3) Creates a comfort zone for the cornerbacks on both sides as they master a specific and smaller technique set.
4) Allows for a more reliable "robber" scheme where Kam can release his coverage to the free safety and go places underneath where the quarterback is not expecting him. When the secondary is on the same page, playing the same positions, there is more reliability in switching off of receivers "on the fly".
Forget the vanity bullpoo about the mythical "shutdown" corner crap. The LOB is a well oiled scheme that even the best passing offenses have trouble defeating. Indeed, on predictable passing downs, they are as good as any group in history. These guys are a team, not just a bunch of guys running around in the same colored jerseys (my favorite Belichick quote).