Of course, this is the reason God smote Sherem in the first place. As the visible symbol of the movement against Jacob, and therefore against the true doctrine of God, the destruction of Sherem redeems Jacob and effects a call to repentance for the people of Nephi. They understand that a conflict between systems has occurred, and that Jacob has emerged as the true connection to a living God.
In the face of this realization, the people who had doubted Jacob now see him in a different light, and the process of repentance for an entire people begins. It is probable that the reason that God did not need Sherem as a preacher was precisely because the need was to reestablish Jacob as preeminent, something that might have been more difficult had there been a redeemed Sherem. Of course Sherem would teach the truth, but the purpose was the restoration of an entire order of things, not just this particular discussion. This becomes clear with Jacob's next statements.